- Definitive materials filed by investment companies. (497)


Contents


The Funds
Introduction	1
Dreyfus Government Cash Management	2
Dreyfus Government Prime Cash Management	6
Management	10
Financial Highlights	11


Your Investment
Shareholder Guide	12
Distributions and Taxes	16
Services for Fund Investors	17

For More Information

See back cover.

The Funds

Dreyfus Government Cash Management
Dreyfus Government Prime Cash Management

INTRODUCTION

Each fund is a money market mutual fund with a separate investment portfolio. The operations and results of one fund are unrelated to those of the other fund. This combined prospectus has been prepared for the convenience of investors so that investors can consider two investment choices in one document.

As money market funds, each is subject to the maturity, quality and diversification requirements of Rule 2a-7, including maintaining an average dollar-weighted portfolio maturity of 90 days or less and buying individual securities with remaining maturities of 13 months or less. These requirements are designed to help money market funds maintain a stable share price.

Generally, each fund is required to invest at least 95% of its assets in the securities of issuers with the highest credit rating or the unrated equivalent as determined by Dreyfus, with the remainder invested in securities with the second-highest credit rating. Dreyfus Government Prime Cash Management invests only in U.S. government securities, and Dreyfus Government Cash Management invests only in U.S. government securities and in repurchase agreements.

An investment in a fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. Although each fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in a fund.

Throughout this prospectus, references to “the fund” apply to all funds, unless otherwise noted.

Dreyfus Government Cash Management

GOAL/APPROACH

The fund seeks as high a level of current income as is consistent with the preservation of capital and maintenance of liquidity. As a money market fund, the fund is subject to maturity, quality and diversification requirements designed to help it maintain a stable share price of $1.00.

To pursue its goal, the fund invests in securities issued or guaranteed as to principal and interest by the U.S. government or its agencies or instrumentalities, and repurchase agreements (including tri-party repurchase agreements). The securities in which the fund invests include those backed by the full faith and credit of the U.S. government and those that are neither insured nor guaranteed by the U.S. government.

Dreyfus Government Cash Management

MAIN RISKS

An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the fund.

The fund’s yield will fluctuate as the short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. Additionally, while the fund has maintained a constant share price since inception, and will continue to try to do so, neither Dreyfus nor its affiliates are required to make a capital infusion, enter into a capital support agreement or take other actions to prevent the fund’s share price from falling below $1.00. The following are the principal risks that could reduce the fund’s income level and/or share price:

Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. The fund’s yield will vary; it is not fixed for a specific period like the yield on a bank certificate of deposit. A sharp and unexpected rise in interest rates could cause a money market fund’s share price to drop below a dollar. However, the extremely short maturities of the securities held in money market portfolios - a means of achieving an overall fund objective of principal safety - reduces their potential for price fluctuation.
U.S. Treasury securities risk. A security backed by the U.S. Treasury or the full faith and credit of the United States is guaranteed only as to the timely payment of interest and principal when held to maturity, but the market prices for such securities are not guaranteed and will fluctuate. Because U.S. Treasury securities trade actively outside the United States, their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Government securities risk . Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities of a security held by the fund does not apply to the market value of such security or to shares of the fund itself. In addition, because many types of U.S. government securities trade actively outside the U.S., their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Counterparty risk. The risk that a counterparty in a repurchase agreement could fail to honor the terms of its agreement.

Dreyfus Government Cash Management

PAST PERFORMANCE

The bar chart and table shown illustrate the risks of investing in the fund. The bar chart shows the changes in the performance of the fund’s Administrative shares from year to year. The table shows the average annual total returns of the fund’s Administrative shares over time. All returns assume reinvestment of dividends and distributions. Of course, past performance (before and after taxes) is no guarantee of future results.

Year-by-year total returns as of 12/31 each year (%)


Best Quarter:	Q3’00	+1.60%
Worst Quarter:	Q2’04	+0.20%

The year-to-date total return of the fund’s Administrative shares as of 3/31/09 was 0.10%.


Average annual total returns
(as of 12/31/08)

1 Year	5 Years	10 Years
2.19%	3.17%	3.35%

For the current yield for Administrative shares, institutions may call toll-free 1-800-346-3621 . Individuals or entities

for whom institutions may purchase or redeem shares should call the institution directly.

Dreyfus Government Cash Management

EXPENSES

As an investor, you pay certain fees and expenses in connection with the fund, which are described in the table below.


Annual fund operating expenses (paid each year as a % of the value of your investment)

Administrative Shares
Management fee	0.20%
Rule 12b-1 fee*	0.10%
Other expenses	0.01%
Treasury Guarantee Program fee**	0.01%
Total annual fund operating expenses***	0.32%

*The fee paid to the fund’s distributor for distributing Administrative shares, for advertising and marketing related to Administrative
shares, and for providing account service and maintenance. Because this fee is paid on an ongoing basis out of fund assets attributable to
Administrative shares, over time it will increase the cost of your investment in Administrative shares and could cost you more than paying
other types of sales charges.
** Reflects the fee paid by the fund to U.S. Treasury Department in connection with the fund’s participation under the Treasury
Department’s Temporary Guarantee Program for Money Market Funds. The fee rate reflects the fund’s participation in the Program,
which terminated on May 1, 2009.
*** For the fiscal year ended January 31, 2009, Dreyfus assumed certain fund expenses pursuant to an agreement in effect, which resulted
in reducing total annual fund operating expenses from 0.32% to 0.31%. This agreement terminates on July 1, 2009.

EXAMPLE

The Example below is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:


1 Year	3 Years	5 Years	10 Years
$33	$103	$180	$406

Dreyfus Government Prime Cash Management

GOAL/APPROACH

To pursue its goal, the fund invests in securities issued or guaranteed as to principal and interest by the U.S. government or its agencies or instrumentalities. The securities in which the fund invests include those backed by the full faith and credit of the U.S. government and those that are neither insured nor guaranteed by the U.S. government.

While the fund is permitted to invest in the full range of securities issued or guaranteed by the U.S. government or its agencies or instrumentalities, the fund currently is managed so that income paid by the fund will be exempt from state and local taxes. Because rules regarding the state and local taxation of dividend income can differ from state to state, investors are urged to consult their tax advisers about the taxation of the fund’s dividend income in their state and locality.

Dreyfus Government Prime Cash Management

MAIN RISKS

Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. The fund’s yield will vary; it is not fixed for a specific period like the yield on a bank certificate of deposit. A sharp and unexpected rise in interest rates could cause a money market fund’s share price to drop below a dollar. However, the extremely short maturities of the securities held in money market portfolios - a means of achieving an overall fund objective of principal safety - reduces their potential for price fluctuation.
U.S. Treasury securities risk. A security backed by the U.S. Treasury or the full faith and credit of the United States is guaranteed only as to the timely payment of interest and principal when held to maturity, but the market prices for such securities are not guaranteed and will fluctuate. Because U.S. Treasury securities trade actively outside the United States, their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Government securities risk . Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities of a security held by the fund does not apply to the market value of such security or to shares of the fund itself. In addition, because many types of U.S. government securities trade actively outside the U.S., their prices may rise and fall as changes in global economic conditions affect the demand for these securities.

Dreyfus Government Prime Cash Management

PAST PERFORMANCE

Year-by-year total returns as of 12/31 each year (%)


Best Quarter:	Q3’00	+1.59%
Worst Quarter:	Q1’04	+0.18%

The year-to-date total returns of the fund’s Administrative shares as of 3/31/09 was 0.05%.


Average annual total returns
(as of 12/31/08)

1 Year	5 Years	10 Years
2.12%	3.13%	3.28%

For the current yield for Administrative shares, institutions may call toll-free 1-800-346-3621 . Individuals or entities

for whom institutions may purchase or redeem shares should call the institution directly.

Dreyfus Government Prime Cash Management

EXPENSES

As an investor, you pay certain fees and expenses in connection with the fund, which are described in the table below.


Annual fund operating expenses (paid each year as a % of the value of your investment)

Administrative Shares
Management fee	0.20%
Rule 12b-1 fee*	0.10%
Other expenses	0.01%
Treasury Guarantee Program fee**	0.02%
Total annual fund operating expenses***	0.33%

*The fee paid to the fund’s distributor for distributing Administrative shares, for advertising and marketing related to Administrative
shares, and for providing account service and maintenance. Because this fee is paid on an ongoing basis out of fund assets attributable to
Administrative shares, over time it will increase the cost of your investment in Administrative shares and could cost you more than paying
other types of sales charges.
** Reflects the fee paid by the fund to U.S. Treasury Department in connection with the fund’s participation under the Treasury
Department’s Temporary Guarantee Program for Money Market Funds. The fee rate reflects the fund’s participation in the Program,
which terminated on May 1, 2009.
*** For the fiscal year ended January 31, 2009, Dreyfus assumed certain fund expenses pursuant to an agreement in effect, which resulted
in reducing total annual fund operating expenses from 0.33% to 0.32%. This agreement terminates on July 1, 2009.

EXAMPLE


1 Year	3 Years	5 Years	10 Years
$34	$106	$185	$418

MANAGEMENT

The investment adviser for the fund is The Dreyfus Corporation (Dreyfus), 200 Park Avenue, New York, New York 10166. Founded in 1947, Dreyfus manages approximately $341 billion in approximately 193 mutual fund portfolios. For the past fiscal year, each fund paid Dreyfus a management fee at an annual rate of 0.20% of the fund’s average daily net assets. A discussion regarding the basis for the board’s approving each fund’s management agreement with Dreyfus is available in the fund’s annual report for the fiscal year ended January 31, 2009. Dreyfus is the primary mutual fund business of The Bank of New York Mellon Corporation (BNY Mellon), a global financial services company focused on helping clients move and manage their financial assets, operating in 34 countries and serving more than 100 markets. BNY Mellon is a leading provider of financial services for institutions, corporations and high-net-worth individuals, providing asset and wealth management, asset servicing, issuer services, and treasury services through a worldwide client-focused team. BNY Mellon has more than $20 trillion in assets under custody and administration and $881 billion in assets under management, and it services more than $11 trillion in outstanding debt. Additional information is available at www.bnymellon.com.

The Dreyfus asset management philosophy is based on the belief that discipline and consistency are important to investment success. For each fund, Dreyfus seeks to establish clear guidelines for portfolio management and to be systematic in making decisions. This approach is designed to provide each fund with a distinct, stable identity. MBSC Securities Corporation (MBSC), a wholly owned subsidiary of Dreyfus, serves as distributor of the fund and for the other funds in the Dreyfus Family of Funds. Dreyfus or MBSC may provide cash payments out of its own resources to financial intermediaries that sell shares of funds in the Dreyfus Family of Funds or provide other services. Such payments are separate from any sales charges, 12b-1 fees and/or shareholder services fees or other expenses that may be paid by a fund to those intermediaries. Because those payments are not made by fund shareholders or the fund, the fund’s total expense ratio will not be affected by any such payments. These payments may be made to intermediaries, including affiliates, that provide shareholder servicing, sub-administration, recordkeeping and/or sub-transfer agency services, marketing support and/or access to sales meetings, sales representatives and management representatives of the financial intermediary. Cash compensation also may be paid from Dreyfus’ or MBSC’s own resources to intermediaries for inclusion of a fund on a sales list, including a preferred or select sales list or in other sales programs. These payments sometimes are referred to as “revenue sharing.” From time to time, Dreyfus or MBSC also may provide cash or non-cash compensation to financial intermediaries or their representatives in the form of occasional gifts; occasional meals, tickets or other entertainment; support for due diligence trips; educational conference sponsorship; support for recognition programs; and other forms of cash or non-cash compensation permissible under broker-dealer regulations. In some cases, these payments or compensation may create an incentive for a financial intermediary or its employees to recommend or sell shares of the fund to you. Please contact your financial representative for details about any payments they or their firm may receive in connection with the sale of fund shares or the provision of services to the fund.

The fund, Dreyfus and MBSC have each adopted a code of ethics that permits its personnel, subject to such code, to invest in securities, including securities that may be purchased or held by the fund. Each code of ethics restricts the personal securities transactions of employees, and requires portfolio managers and other investment personnel to comply with the code’s preclearance and disclosure procedures. The primary purpose of the respective codes is to ensure that personal trading by employees does not disadvantage any of the firms’ other clients.

FINANCIAL HIGHLIGHTS

These financial highlights describe the performance of the fund’s Administrative shares for the fiscal periods indicated. “Total return” shows how much your investment in the fund would have increased (or decreased) during each period, assuming you had reinvested all dividends and distributions. These financial highlights have been audited by Ernst & Young LLP, an independent registered public accounting firm, whose report, along with the fund’s financial statements, is included in the annual report, which is available upon request.


			Year Ended January 31,

Dreyfus Government Cash Management	2009	2008	2007	2006	2005
Per Share Data ($):
Net asset value, beginning of period	1.00	1.00	1.00	1.00	1.00
Investment Operations:
Investment income--net	.019	.047	.048	.031	.012
Distributions:
Dividends from investment income-net	(.019)	(.047)	(.048)	(.031)	(.012)
Net asset value, end of period	1.00	1.00	1.00	1.00	1.00
Total Return (%)	1.91	4.83	4.88	3.12	1.16
Ratios/Supplemental Data (%):
Ratio of total expenses to average net assets	.31	.30	.30	.30	.30
Ratio of net investment income to average net assets	1.54	4.63	4.79	3.05	1.10
Net Assets, end of period ($ x 1,000,000)	2,258	693	320	240	313


			Year Ended January 31,
Dreyfus Government Prime Cash
Management	2009	2008	2007	2006	2005
Per Share Data ($):
Net asset value, beginning of period	1.00	1.00	1.00	1.00	1.00
Investment Operations:
Investment income--net	.018	.047	.047	.030	.011
Distributions:
Dividends from investment income--net	(.018)	(.047)	(.047)	(.030)	(.011)
Net asset value, end of period	1.00	1.00	1.00	1.00	1.00
Total Return (%)	1.81	4.80	4.85	3.08	1.11
Ratios/Supplemental Data (%):
Ratio of total expenses to average net assets	.32	.30	.30	.30	.30
Ratio of net expenses to average net assets	.32	.30	.30	.30	.30
Ratio of net investment income to average net assets	1.54	4.57	4.76	3.11	1.09
Net Assets, end of period ($ x 1,000,000)	693	307	314	210	200

Your Investment

SHAREHOLDER GUIDE

Each fund is designed for institutional investors , particularly banks, acting for themselves or in a fiduciary, advisory, agency, custodial or similar capacity. Generally, each investor will be required to open a single master account with the fund for all purposes. In certain cases, the fund may request investors to maintain separate master accounts for shares held by the investor (i) for its own account, for the account of other institutions and for accounts for which the institution acts as a fiduciary, and (ii) for accounts for which the investor acts in some other capacity. An institution may arrange with the fund's transfer agent for sub-accounting services and will be charged directly for the cost of such services. Institutions purchasing Administrative shares for the benefit of their clients may impose policies, limitations and fees which are different from those described in this prospectus.

Valuing Shares

Your price for Administrative shares is the net asset value per share (NAV).

The fund’s securities are valued at amortized cost, which does not take into account unrealized gains or losses. As a result, portfolio securities are valued at their acquisition cost, adjusted over time based on the discounts or premiums reflected in their purchase price. Each fund uses this valuation method pursuant to Rule 2a-7 under the Investment Company Act of 1940 in order to be able to price its shares at $1.00 per share. In accordance with Rule 2a-7, each fund is subject to certain maturity, quality and diversification requirements to help maintain the $1.00 share price.

When calculating its NAV, a fund compares the NAV using amortized cost to its NAV using available market quotations or market equivalents which generally are provided by an independent pricing service approved by the fund’s board. The pricing service’s procedures are reviewed under the general supervision of the board.

All times are Eastern time.

How to Buy Shares

Each fund’s NAV is generally calculated at 12:00 noon, 5:00 p.m. and 8:00 p.m. on days the New York Stock Exchange is open for regular business. An order will be priced at the next NAV calculated after the order is received in proper form by the fund’s transfer agent or other authorized entity. Each fund’s investments are valued based on amortized cost. As a result, portfolio securities are valued at their acquisition cost, adjusted for discounts or premiums reflected in their purchase price. This method of valuation is designed to enable the fund to price its shares at $1.00 per share.

As to Dreyfus Government Cash Management, orders in proper form placed prior to 12:00 noon or 5:00 p.m., and payments for which are received in or converted into Federal Funds by the fund’s custodian by 6:00 p.m., will become effective at the price determined at 12:00 noon or 5:00 p.m., respectively, on that day. In either case, shares purchased will receive the dividend declared on that day.

As to Dreyfus Government Prime Cash Management, orders in proper form placed prior to 12:00 noon or 3:00 p.m., and payments for which are received in or converted into Federal Funds by the fund’s custodian by 6:00 p.m., will become effective at the price determined at 12:00 noon or 5:00 p.m., respectively, on that day. In either case, shares purchased will receive the dividend declared on that day. Orders for shares placed between 3:00 p.m. and 5:00 p.m. will not be accepted and executed, and notice of the purchase order being rejected will be given to the institution placing the order, and any funds received will be returned promptly to the sending institution.

As to each fund, orders effected through a compatible computer facility after 5:00 p.m., but by 8:00 p.m., will become effective at the price determined at 8:00 p.m. on that day, if Federal Funds are received by the fund’s

custodian by 11:00 a.m. on the following business day. In this case, shares purchased will start earning dividends on the business day following the date the order became effective. Orders effected in proper form between 5:00 p.m. and 8:00 p.m., by a means other than a compatible computer facility, will become effective on the following business day.

For all funds, all times are Eastern time.


Minimum investments

	Initial	Additional
Administrative	$10,000,000*	none
Shares

* The minimum initial investment in Administrative shares is
$10,000,000, unless: (a) the investor has invested at least $10,000,000
in the aggregate among any Dreyfus Cash Management fund, Dreyfus
Institutional Cash Advantage Fund and Dreyfus Institutional Cash
Advantage Plus Fund (including in any class of a fund); or (b) the
investor has, in the opinion of Dreyfus Cash Investment Services
Division, adequate intent and availability of assets to reach a future
level of investment of $10,000,000 among the funds named above.

How to Sell Shares

You may sell (redeem) shares at any time by wire, telephone, or compatible computer facility. Shares will be sold at the next determined NAV.

Your shares will be sold at the next NAV calculated after your order is received in proper form by the fund’s transfer agent or other authorized entity. Any certificates representing fund shares being sold must be returned with your redemption request. Your order will be processed promptly and you will generally receive the proceeds of a redemption within a week.

For all funds, all times are Eastern time.

Applicable to all funds:

The processing of redemptions and the delivery of the proceeds may be delayed beyond the same or next business day, depending on the circumstance, for any period (i) during which New York Stock Exchange is closed (other than on holidays or weekends), or during which trading on the New York Stock Exchange is restricted; (ii) when an emergency exists that makes difficult the disposal of securities owned by a fund or the determination of the fair value of the fund’s net assets; or (iii) as permitted by order of the Securities and Exchange Commission for the protection of fund shareholders. For these purposes, the Securities and Exchange Commission determines the conditions under which trading shall be deemed to be restricted and an emergency shall be deemed to exist. Any certificates representing fund shares being sold must be returned with the redemption request.

Before selling recently purchased shares, please note that if the fund has not yet collected payment for the shares being sold, it may delay sending the proceeds for up to eight business days or until it has collected payment.

General Policies

Unless you decline telephone privileges on your application, you may be responsible for any fraudulent telephone or online order as long as the fund’s transfer agent takes reasonable measures to confirm that instructions are genuine.

Money market funds generally are used by investors for short-term investments, often in place of bank checking or savings accounts, or for cash management purposes. Investors value the ability to add and withdraw their funds quickly, without restriction. For this reason, although Dreyfus discourages excessive trading and other abusive trading practices, the fund has not adopted policies and procedures, or imposed redemption fees or other restrictions such as minimum holding periods, to deter frequent purchases and redemptions of fund shares. Dreyfus also believes that money market funds, such as the funds, are not targets of abusive trading practices, because money market funds seek to maintain a $1.00 per share price and typically do not fluctuate in value based on market prices. However, frequent purchases and redemptions of a fund’s shares could increase the fund’s transaction costs, such as market spreads and custodial fees, and may interfere with the efficient management of a fund’s portfolio, which could detract from the fund’s performance. Accordingly, each fund reserves the right to refuse any purchase or exchange request. Funds in the Dreyfus Family of Funds that are not money market mutual funds have approved policies and procedures that are intended to discourage and prevent abusive trading practices in those mutual funds, which may apply to exchanges from or into a fund. If you plan to exchange your fund shares for shares of another Dreyfus fund, please read the prospectus of that other Dreyfus fund for more information.

Each fund also reserves the right to:

refuse any purchase or exchange request
change or discontinue its exchange privilege, or temporarily suspend the privilege during unusual market conditions
change its minimum investment amounts
“redeem in kind,” or make payments in securities rather than cash, if the amount redeemed is large enough to affect fund operations (for example, if it exceeds 1% of the fund’s assets). Investors are urged to call 1-800- 242-2224 before effecting any large transactions.

Each fund also may process purchase and sale orders and calculate its NAV on days the fund’s primary trading markets are open and the fund’s management determines to do so.

DISTRIBUTIONS AND TAXES

Each fund earns dividends, interest and other income from its investments, and distributes this income (less expenses) to shareholders as dividends. Each fund also realizes capital gains from its investments, and distributes these gains (less any losses) to shareholders as capital gain distributions. Each fund normally pays dividends once a month and capital gain distributions annually. Fund dividends and capital gain distributions will be reinvested in the fund unless you instruct the fund otherwise. There are no fees or sales charges on reinvestments.

Dividends and other distributions paid by the taxable money market funds are subject to federal income tax, and may be subject to state and local taxes (unless you are investing through a tax-advantaged retirement account).

Each fund anticipates that virtually all dividends paid to you will be exempt from federal income taxes. However, for federal tax purposes, certain distributions, such as distributions of short-term capital gains, are taxable to you as ordinary income, while long-term capital gains are taxable to you as capital gains.

Distributions that are federally taxable as ordinary income or capital gains are generally subject to the state's personal income taxes. However, because the funds invest principally in U.S. Government securities, some income may not be subject to state income taxes.

The tax status of any distribution generally is the same regardless of how long you have been in the fund and whether you reinvest your distributions or take them in cash.

If you buy shares of a fund when the fund has realized but not yet distributed income or capital gains, you will be “buying a dividend” by paying the full price for the shares and then receiving a portion back in the form of a taxable distribution.

Your sale of shares, including exchanges into other funds, may result in a capital gain or loss for tax purposes. A capital gain or loss on your investment in the fund generally is the difference between the cost of your shares and the amount you receive when you sell them.

The tax status of your distributions will be detailed in your annual tax statement from the fund. Because everyone’s tax situation is unique, please consult your tax adviser before investing.

SERVICES FOR FUND INVESTORS

Account statements

Every Dreyfus Fund investor automatically receives regular account statements. Each investor will also be sent a yearly statement detailing the tax characteristics of any dividends and distributions the investor has received.


Contents


The Funds
Introduction	1
Dreyfus Government Cash Management	2
Dreyfus Government Prime Cash Management	6
Management	10
Financial Highlights	11


Your Investment
Shareholder Guide	12
Distributions and Taxes	15
Services for Fund Investors	16

For More Information

See back cover.

The Funds

Dreyfus Government Cash Management
Dreyfus Government Prime Cash Management

INTRODUCTION

Throughout this prospectus, references to “the fund” apply to all funds, unless otherwise noted.

Dreyfus Government Cash Management

GOAL/APPROACH

Dreyfus Government Cash Management

MAIN RISKS

Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. The fund’s yield will vary; it is not fixed for a specific period like the yield on a bank certificate of deposit. A sharp and unexpected rise in interest rates could cause a money market fund’s share price to drop below a dollar. However, the extremely short maturities of the securities held in money market portfolios - a means of achieving an overall fund objective of principal safety - reduces their potential for price fluctuation.
U.S. Treasury securities risk. A security backed by the U.S. Treasury or the full faith and credit of the United States is guaranteed only as to the timely payment of interest and principal when held to maturity, but the market prices for such securities are not guaranteed and will fluctuate. Because U.S. Treasury securities trade actively outside the United States, their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Government securities risk . Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities of a security held by the fund does not apply to the market value of such security or to shares of the fund itself. In addition, because many types of U.S. government securities trade actively outside the U.S., their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Counterparty risk. The risk that a counterparty in a repurchase agreement could fail to honor the terms of its agreement.

Dreyfus Government Cash Management

PAST PERFORMANCE

The bar chart and table shown illustrate the risks of investing in the fund. The bar chart shows the changes in the performance of the fund’s Agency shares from year to year. The table shows the average annual total returns of the fund’s Agency shares over time. All returns assume reinvestment of dividends and distributions. Of course, past performance (before and after taxes) is no guarantee of future results.

Year-by-year total returns as of 12/31 each year (%)


Best Quarter:	Q1’08	+0.86%
Worst Quarter:	Q4’08	+0.27%

The year-to-date total return of the fund’s Agency shares as of 3/31/09 was 0.12%.


Average annual total returns
(as of 12/31/08)

	Since
	Inception
1 Year	(10/1/07)
2.24%	2.69%

For the current yield for Agency shares, institutions may call toll-free 1-800-346-3621 . Individuals or entities

for whom institutions may purchase or redeem shares should call the institution directly.

Dreyfus Government Cash Management

EXPENSES

As an investor, you pay certain fees and expenses in connection with the fund, which are described in the table below.


Annual fund operating expenses (paid each year as a % of the value of your investment)

Agency Shares
Management fee	0.20%
Rule 12b-1 fee*	0.06%
Other expenses	0.01%
Treasury Guarantee Program fee**	0.01%
Total annual fund operating expenses***	0.28%

*The fee paid to the fund’s distributor for distributing Agency shares, for advertising and marketing related to Agency shares, and for
providing account service and maintenance. Because this fee is paid on an ongoing basis out of fund assets attributable to Agency shares,
over time it will increase the cost of your investment in Agency shares and could cost you more than paying other types of sales charges.
** Reflects the fee paid by the fund to U.S. Treasury Department in connection with the fund’s participation under the Treasury
Department’s Temporary Guarantee Program for Money Market Funds. The fee rate reflects the fund’s participation in the Program,
which terminated on May 1, 2009.
*** For the fiscal year ended January 31, 2009, Dreyfus assumed certain fund expenses pursuant to an agreement in effect, which resulted
in reducing total annual fund operating expenses from 0.28% to 0.27%. This agreement terminates on July 1, 2009.

EXAMPLE


1 Year	3 Years	5 Years	10 Years
$29	$90	$157	$356

Dreyfus Government Prime Cash Management

GOAL/APPROACH

Dreyfus Government Prime Cash Management

MAIN RISKS

Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. The fund’s yield will vary; it is not fixed for a specific period like the yield on a bank certificate of deposit. A sharp and unexpected rise in interest rates could cause a money market fund’s share price to drop below a dollar. However, the extremely short maturities of the securities held in money market portfolios - a means of achieving an overall fund objective of principal safety - reduces their potential for price fluctuation.
U.S. Treasury securities risk. A security backed by the U.S. Treasury or the full faith and credit of the United States is guaranteed only as to the timely payment of interest and principal when held to maturity, but the market prices for such securities are not guaranteed and will fluctuate. Because U.S. Treasury securities trade actively outside the United States, their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Government securities risk . Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities of a security held by the fund does not apply to the market value of such security or to shares of the fund itself. In addition, because many types of U.S. government securities trade actively outside the U.S., their prices may rise and fall as changes in global economic conditions affect the demand for these securities.

Dreyfus Government Prime Cash Management

PAST PERFORMANCE

Year-by-year total returns as of 12/31 each year (%)


Best Quarter:	Q1’08	+0.82%
Worst Quarter:	Q4’08	+0.27%

The year-to-date total returns of the fund’s Agency shares as of 3/31/09 was 0.06%.


Average annual total returns
(as of 12/31/08)

	Since
	Inception
1 Year	(10/1/07)
2.16%	2.64%

Dreyfus Government Prime Cash Management

EXPENSES

As an investor, you pay certain fees and expenses in connection with the fund, which are described in the table below.


Annual fund operating expenses (paid each year as a % of the value of your investment)

Agency Shares
Management fee	0.20%
Rule 12b-1 fee*	0.06%
Other expenses	0.01%
Treasury Guarantee Program fee**	0.02%
Total annual fund operating expenses***	0.29%

*The fee paid to the fund’s distributor for distributing Agency shares, for advertising and marketing related to Agency shares, and for
providing account service and maintenance. Because this fee is paid on an ongoing basis out of fund assets attributable to Agency shares,
over time it will increase the cost of your investment in Agency shares and could cost you more than paying other types of sales charges.
** Reflects the fee paid by the fund to U.S. Treasury Department in connection with the fund’s participation under the Treasury
Department’s Temporary Guarantee Program for Money Market Funds. The fee rate reflects the fund’s participation in the Program,
which terminated on May 1, 2009.
*** For the fiscal year ended January 31, 2009, Dreyfus assumed certain fund expenses pursuant to an agreement in effect, which resulted
in reducing total annual fund operating expenses from 0.29% to 0.28%. This agreement terminates on July 1, 2009.

EXAMPLE


1 Year	3 Years	5 Years	10 Years
$30	$93	$163	$368

MANAGEMENT

MBSC Securities Corporation (MBSC), a wholly owned subsidiary of Dreyfus, serves as distributor of the fund and for the other funds in the Dreyfus Family of Funds. Dreyfus or MBSC may provide cash payments out of its own resources to financial intermediaries that sell shares of funds in the Dreyfus Family of Funds or provide other services. Such payments are separate from any sales charges, 12b-1 fees and/or shareholder services fees or other expenses that may be paid by a fund to those intermediaries. Because those payments are not made by fund shareholders or the fund, the fund’s total expense ratio will not be affected by any such payments. These payments may be made to intermediaries, including affiliates, that provide shareholder servicing, sub-administration, recordkeeping and/or sub-transfer agency services, marketing support and/or access to sales meetings, sales representatives and management representatives of the financial intermediary. Cash compensation also may be paid from Dreyfus’ or MBSC’s own resources to intermediaries for inclusion of a fund on a sales list, including a preferred or select sales list or in other sales programs. These payments sometimes are referred to as “revenue sharing.” From time to time, Dreyfus or MBSC also may provide cash or non-cash compensation to financial intermediaries or their representatives in the form of occasional gifts; occasional meals, tickets or other entertainment; support for due diligence trips; educational conference sponsorship; support for recognition programs; and other forms of cash or non-cash compensation permissible under broker-dealer regulations. In some cases, these payments or compensation may create an incentive for a financial intermediary or its employees to recommend or sell shares of the fund to you. Please contact your financial representative for details about any payments they or their firm may receive in connection with the sale of fund shares or the provision of services to the fund.

FINANCIAL HIGHLIGHTS

These financial highlights describe the performance of the fund’s Agency shares for the fiscal periods indicated. “Total return” shows how much your investment in the fund would have increased (or decreased) during each period, assuming you had reinvested all dividends and distributions. These financial highlights have been audited by Ernst & Young LLP, an independent registered public accounting firm, whose report, along with the fund’s financial statements, is included in the annual report, which is available upon request.


		Year Ended January 31,

Dreyfus Government Cash Management	2009	2008 a
Per Share Data ($):
Net asset value, beginning of period	1.00	1.00
Investment Operations:
Investment income--net	.019	.014
Distributions:
Dividends from investment income--net	(.019)	(.014)
Net asset value, end of period	1.00	1.00
Total Return (%)	1.96	4.30 b
Ratios/Supplemental Data (%):
Ratio of total expenses to average net assets	.27	.26 b
Ratio of net investment income to average net assets	1.58	4.67 b
Net Assets, end of period ($ x 1,000,000)	86	2

a From October 1, 2007 (commencement of initial offering) to January 31, 2008.
b Annualized.


		Year Ended January 31,
Dreyfus Government Prime Cash
Management	2009	2008 a
Per Share Data ($):
Net asset value, beginning of period	1.00	1.00
Investment Operations:
Investment income--net	.018	.015
Distributions:
Dividends from investment income--net	(.018)	(.015)
Net asset value, end of period	1.00	1.00
Total Return (%)	1.85	4.33 b
Ratios/Supplemental Data (%):
Ratio of total expenses to average net assets	.28	.26 b
Ratio of net expenses to average net assets	.28	.26 b
Ratio of net investment income to average net assets	1.58	4.61 b
Net Assets, end of period ($ x 1,000,000)	41	10

a From October 1, 2007 (commencement of initial offering) to January 31, 2008.
b Annualized.

Your Investment

SHAREHOLDER GUIDE

Each fund is designed for institutional investors , particularly banks, acting for themselves or in a fiduciary, advisory, agency, custodial or similar capacity. Generally, each investor will be required to open a single master account with the fund for all purposes. In certain cases, the fund may request investors to maintain separate master accounts for shares held by the investor (i) for its own account, for the account of other institutions and for accounts for which the institution acts as a fiduciary, and (ii) for accounts for which the investor acts in some other capacity. An institution may arrange with the fund's transfer agent for sub-accounting services and will be charged directly for the cost of such services. Institutions purchasing Agency shares for the benefit of their clients may impose policies, limitations and fees which are different from those described in this prospectus.

Valuing Shares

Your price for Agency shares is the net asset value per share (NAV).

All times are Eastern time.

How to Buy Shares

For all funds, all times are Eastern time.


Minimum investments

	Initial	Additional
Agency Shares	$10,000,000*	none

* The minimum initial investment in Agency shares is $10,000,000,
unless: (a) the investor has invested at least $10,000,000 in the
aggregate among any Dreyfus Cash Management fund, Dreyfus
Institutional Cash Advantage Fund and Dreyfus Institutional Cash
Advantage Plus Fund (including in any class of a fund); or (b) the
investor has, in the opinion of Dreyfus Cash Investment Services
Division, adequate intent and availability of assets to reach a future
level of investment of $10,000,000 among the funds named above.

How to Sell Shares

You may sell (redeem) shares at any time by wire, telephone, or compatible computer facility. Shares will be sold at the next determined NAV.

For all funds, all times are Eastern time.

Applicable to all funds:

General Policies

Each fund also reserves the right to:

refuse any purchase or exchange request
change or discontinue its exchange privilege, or temporarily suspend the privilege during unusual market conditions
change its minimum investment amounts
“redeem in kind,” or make payments in securities rather than cash, if the amount redeemed is large enough to affect fund operations (for example, if it exceeds 1% of the fund’s assets). Investors are urged to call 1-800- 242-2224 before effecting any large transactions.

Each fund also may process purchase and sale orders and calculate its NAV on days the fund’s primary trading markets are open and the fund’s management determines to do so.

DISTRIBUTIONS AND TAXES

The tax status of any distribution generally is the same regardless of how long you have been in the fund and whether you reinvest your distributions or take them in cash.

The tax status of your distributions will be detailed in your annual tax statement from the fund. Because everyone’s tax situation is unique, please consult your tax adviser before investing.

SERVICES FOR FUND INVESTORS

Account statements

NOTES


Contents


The Funds
Introduction	1
Dreyfus Government Cash Management	2
Dreyfus Government Prime Cash Management	6
Management	10
Financial Highlights	11


Your Investment
Shareholder Guide	12
Distributions and Taxes	15
Services for Fund Investors	16

For More Information

See back cover.

The Funds

Dreyfus Government Cash Management
Dreyfus Government Prime Cash Management

INTRODUCTION

Throughout this prospectus, references to “the fund” apply to all funds, unless otherwise noted.

Dreyfus Government Cash Management

GOAL/APPROACH

Dreyfus Government Cash Management

MAIN RISKS

Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. The fund’s yield will vary; it is not fixed for a specific period like the yield on a bank certificate of deposit. A sharp and unexpected rise in interest rates could cause a money market fund’s share price to drop below a dollar. However, the extremely short maturities of the securities held in money market portfolios - a means of achieving an overall fund objective of principal safety - reduces their potential for price fluctuation.
U.S. Treasury securities risk. A security backed by the U.S. Treasury or the full faith and credit of the United States is guaranteed only as to the timely payment of interest and principal when held to maturity, but the market prices for such securities are not guaranteed and will fluctuate. Because U.S. Treasury securities trade actively outside the United States, their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Government securities risk . Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities of a security held by the fund does not apply to the market value of such security or to shares of the fund itself. In addition, because many types of U.S. government securities trade actively outside the U.S., their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Counterparty risk. The risk that a counterparty in a repurchase agreement could fail to honor the terms of its agreement.

Dreyfus Government Cash Management

PAST PERFORMANCE

The bar chart and table shown illustrate the risks of investing in the fund. The bar chart shows the changes in the performance of the fund’s Institutional shares from year to year. The table shows the average annual total returns of the fund’s Institutional shares over time. All returns assume reinvestment of dividends and distributions. Of course, past performance (before and after taxes) is no guarantee of future results.

Year-by-year total returns as of 12/31 each year (%)


Best Quarter:	Q3’00	+1.63%
Worst Quarter:	Q2’04	+0.22%

The year-to-date total return of the fund’s Institutional shares as of 3/31/09 was 0.13%.


Average annual total returns
	(as of 12/31/08)
1 Year	5 Years	10 Years
2.29%	3.27%	3.45%

For the current yield for Institutional shares, institutions may call toll-free 1-800-346-3621 . Individuals or entities

for whom institutions may purchase or redeem shares should call the institution directly.

Dreyfus Government Cash Management

EXPENSES

As an investor, you pay certain fees and expenses in connection with the fund, which are described in the table below.


Annual fund operating expenses (paid each year as a % of the value of your investment)

Institutional Shares
Management fee	0.20%
Other expenses	0.01%
Treasury Guarantee Program fee*	0.02%
Total annual fund operating expenses**	0.23%

* Reflects the fee paid by the fund to U.S. Treasury Department in connection with the fund’s participation under the Treasury
Department’s Temporary Guarantee Program for Money Market Funds. The fee rate reflects the fund’s participation in the Program,
which terminated on May 1, 2009.
** For the fiscal year ended January 31, 2009, Dreyfus assumed certain fund expenses pursuant to an agreement in effect, which resulted
in reducing total annual fund operating expenses from 0.23% to 0.22%. This agreement terminates on July 1, 2009.

EXAMPLE


1 Year	3 Years	5 Years	10 Years
$24	$74	$130	$293

Dreyfus Government Prime Cash Management

GOAL/APPROACH

Dreyfus Government Prime Cash Management

MAIN RISKS

Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. The fund’s yield will vary; it is not fixed for a specific period like the yield on a bank certificate of deposit. A sharp and unexpected rise in interest rates could cause a money market fund’s share price to drop below a dollar. However, the extremely short maturities of the securities held in money market portfolios - a means of achieving an overall fund objective of principal safety - reduces their potential for price fluctuation.
U.S. Treasury securities risk. A security backed by the U.S. Treasury or the full faith and credit of the United States is guaranteed only as to the timely payment of interest and principal when held to maturity, but the market prices for such securities are not guaranteed and will fluctuate. Because U.S. Treasury securities trade actively outside the United States, their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Government securities risk . Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities of a security held by the fund does not apply to the market value of such security or to shares of the fund itself. In addition, because many types of U.S. government securities trade actively outside the U.S., their prices may rise and fall as changes in global economic conditions affect the demand for these securities.

Dreyfus Government Prime Cash Management

PAST PERFORMANCE

Year-by-year total returns as of 12/31 each year (%)


Best Quarter:	Q3 ’00	+1.62%
Worst Quarter:	Q2 ’04	+0.21%

The year-to-date total returns of the fund’s Institutional shares as of 3/31/09 was 0.08%.


Average annual total returns
(as of 12/31/08)

1 Year	5 Years	10 Years
2.22%	3.23%	3.38%

Dreyfus Government Prime Cash Management

EXPENSES

As an investor, you pay certain fees and expenses in connection with the fund, which are described in the table below.


Annual fund operating expenses (paid each year as a % of the value of your investment)

Institutional Shares
Management fee	0.20%
Other expenses	0.01%
Treasury Guarantee Program fee*	0.02%
Total annual fund operating expenses**	0.23%

EXAMPLE

The Example below is intended to help you compare the cost of investing in the fund with the cost of investing other mutual funds. The Example assumes that you invest $10,000 in the fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:


1 Year	3 Years	5 Years	10 Years
$24	$74	$130	$293

MANAGEMENT

FINANCIAL HIGHLIGHTS

These financial highlights describe the performance of the fund’s Institutional shares for the fiscal periods indicated. “Total return” shows how much your investment in the fund would have increased (or decreased) during each period, assuming you had reinvested all dividends and distributions. These financial highlights have been audited by Ernst & Young LLP, an independent registered public accounting firm, whose report, along with the fund’s financial statements, is included in the annual report, which is available upon request.


			Year Ended January 31,

Dreyfus Government Cash Management	2009	2008	2007	2006	2005
Per Share Data ($):
Net asset value, beginning of period	1.00	1.00	1.00	1.00	1.00
Investment Operations:
Investment income--net	.020	.048	.049	.032	.013
Distributions:
Dividends from investment income-net	(.020)	(.048)	(.049)	(.032)	(.013)
Net asset value, end of period	1.00	1.00	1.00	1.00	1.00
Total Return (%)	2.01	4.93	4.99	3.23	1.26
Ratios/Supplemental Data (%):
Ratio of total expenses to average net assets	.22	.20	.20	.20	.20
Ratio of net investment income to average net assets	1.63	4.73	4.89	3.15	1.20
Net Assets, end of period ($ x 1,000,000)	33,715	9,303	3,118	2,842	3,571


			Year Ended January 31,

Dreyfus Government Prime Cash Management	2009	2008	2007	2006	2005
Per Share Data ($):
Net asset value, beginning of period	1.00	1.00	1.00	1.00	1.00
Investment Operations:
Investment income--net	.019	.048	.048	.031	.012
Distributions:
Dividends from investment income--net	(.019)	(.048)	(.048)	(.031)	(.012)
Net asset value, end of period	1.00	1.00	1.00	1.00	1.00
Total Return (%)	1.91	4.91	4.95	3.18	1.21
Ratios/Supplemental Data (%):
Ratio of total expenses to average net assets	.22	.20	.20	.20	.20
Ratio of net expenses to average net assets	.22	.20	.20	.20	.20
Ratio of net investment income to average net assets	1.64	4.67	4.86	3.21	1.19
Net Assets, end of period ($ x 1,000,000)	6,439	2,327	1,005	773	537

Your Investment

SHAREHOLDER GUIDE

Each fund is designed for institutional investors , particularly banks, acting for themselves or in a fiduciary, advisory, agency, custodial or similar capacity. Generally, each investor will be required to open a single master account with the fund for all purposes. In certain cases, the fund may request investors to maintain separate master accounts for shares held by the investor (i) for its own account, for the account of other institutions and for accounts for which the institution acts as a fiduciary, and (ii) for accounts for which the investor acts in some other capacity. An institution may arrange with the fund's transfer agent for sub-accounting services and will be charged directly for the cost of such services. Institutions purchasing Institutional shares for the benefit of their clients may impose policies, limitations and fees which are different from those described in this prospectus.

Valuing Shares

Your price for Institutional shares is the net asset value per share (NAV).

All times are Eastern time.

How to Buy Shares

For all funds, all times are Eastern time.


Minimum investments

	Initial	Additional
Institutional Shares	$10,000,000*	none

* The minimum initial investment in Institutional shares is $10,000,000,
unless: (a) the investor has invested at least $10,000,000 in the
aggregate among any Dreyfus Cash Management fund, Dreyfus
Institutional Cash Advantage Fund and Dreyfus Institutional Cash
Advantage Plus Fund (including in any class of a fund); or (b) the
investor has, in the opinion of Dreyfus Cash Investment Services
Division, adequate intent and availability of assets to reach a future
level of investment of $10,000,000 among the funds named above.

How to Sell Shares

You may sell (redeem) shares at any time by wire, telephone, or compatible computer facility. Shares will be sold at the next determined NAV.

For all funds, all times are Eastern time.

Applicable to all funds:

General Policies

Each fund also reserves the right to:

refuse any purchase or exchange request
change or discontinue its exchange privilege, or temporarily suspend the privilege during unusual market conditions
change its minimum investment amounts
“redeem in kind,” or make payments in securities rather than cash, if the amount redeemed is large enough to affect fund operations (for example, if it exceeds 1% of the fund’s assets). Investors are urged to call 1-800- 242-2224 before effecting any large transactions.

Each fund also may process purchase and sale orders and calculate its NAV on days the fund’s primary trading markets are open and the fund’s management determines to do so.

DISTRIBUTIONS AND TAXES

The tax status of any distribution generally is the same regardless of how long you have been in the fund and whether you reinvest your distributions or take them in cash.

The tax status of your distributions will be detailed in your annual tax statement from the fund. Because everyone’s tax situation is unique, please consult your tax adviser before investing.

SERVICES FOR FUND INVESTORS

Account statements

NOTES


Contents


The Funds
Introduction	1
Dreyfus Government Cash Management	2
Dreyfus Government Prime Cash Management	6
Management	10
Financial Highlights	11


Your Investment
Shareholder Guide	12
Distributions and Taxes	15
Services for Fund Investors	16

For More Information

See back cover.

The Funds

Dreyfus Government Cash Management
Dreyfus Government Prime Cash Management

INTRODUCTION

Throughout this prospectus, references to “the fund” apply to all funds, unless otherwise noted.

Dreyfus Government Cash Management

GOAL/APPROACH

Dreyfus Government Cash Management

MAIN RISKS

Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. The fund’s yield will vary; it is not fixed for a specific period like the yield on a bank certificate of deposit. A sharp and unexpected rise in interest rates could cause a money market fund’s share price to drop below a dollar. However, the extremely short maturities of the securities held in money market portfolios - a means of achieving an overall fund objective of principal safety - reduces their potential for price fluctuation.
U.S. Treasury securities risk. A security backed by the U.S. Treasury or the full faith and credit of the United States is guaranteed only as to the timely payment of interest and principal when held to maturity, but the market prices for such securities are not guaranteed and will fluctuate. Because U.S. Treasury securities trade actively outside the United States, their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Government securities risk . Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities of a security held by the fund does not apply to the market value of such security or to shares of the fund itself. In addition, because many types of U.S. government securities trade actively outside the U.S., their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Counterparty risk. The risk that a counterparty in a repurchase agreement could fail to honor the terms of its agreement.

Dreyfus Government Cash Management

PAST PERFORMANCE

The bar chart and table shown illustrate the risks of investing in the fund. The bar chart shows the changes in the performance of the fund’s Investor shares from year to year. The table shows the average annual total returns of the fund’s Investor shares over time. All returns assume reinvestment of dividends and distributions. Of course, past performance (before and after taxes) is no guarantee of future results.

Year-by-year total returns as of 12/31 each year (%)


Best Quarter:	Q3’00	+1.56%
Worst Quarter:	Q2’04	+0.16%

The year-to-date total return of the fund’s Investor shares as of 3/31/09 was 0.07%.


Average annual total returns
(as of 12/31/08)

1 Year	5 Years	10 Years
2.04%	3.02%	3.19%

For the current yield for Investor shares, institutions may call toll-free 1-800-346-3621 . Individuals or entities

for whom institutions may purchase or redeem shares should call the institution directly.

Dreyfus Government Cash Management

EXPENSES

As an investor, you pay certain fees and expenses in connection with the fund, which are described in the table below.


Annual fund operating expenses (paid each year as a % of the value of your investment)

Investor Shares
Management fee	0.20%
Rule 12b-1 fee*	0.25%
Other expenses	0.01%
Treasury Guarantee Program fee**	0.01%
Total annual fund operating expenses***	0.47%

*The fee paid to the fund’s distributor for distributing Investor shares, for advertising and marketing related to Investor shares, and for
providing account service and maintenance. Because this fee is paid on an ongoing basis out of fund assets attributable to Investor shares,
over time it will increase the cost of your investment in Investor shares and could cost you more than paying other types of sales charges.
** Reflects the fee paid by the fund to U.S. Treasury Department in connection with the fund’s participation under the Treasury
Department’s Temporary Guarantee Program for Money Market Funds. The fee rate reflects the fund’s participation in the Program,
which terminated on May 1, 2009.
*** For the fiscal year ended January 31, 2009, Dreyfus assumed certain fund expenses pursuant to an agreement in effect, which resulted
in reducing total annual fund operating expenses from 0.47% to 0.46%. This agreement terminates on July 1, 2009.

EXAMPLE


1 Year	3 Years	5 Years	10 Years
$48	$151	$263	$591

Dreyfus Government Prime Cash Management

GOAL/APPROACH

Dreyfus Government Prime Cash Management

MAIN RISKS

Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. The fund’s yield will vary; it is not fixed for a specific period like the yield on a bank certificate of deposit. A sharp and unexpected rise in interest rates could cause a money market fund’s share price to drop below a dollar. However, the extremely short maturities of the securities held in money market portfolios - a means of achieving an overall fund objective of principal safety - reduces their potential for price fluctuation.
U.S. Treasury securities risk. A security backed by the U.S. Treasury or the full faith and credit of the United States is guaranteed only as to the timely payment of interest and principal when held to maturity, but the market prices for such securities are not guaranteed and will fluctuate. Because U.S. Treasury securities trade actively outside the United States, their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Government securities risk . Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities of a security held by the fund does not apply to the market value of such security or to shares of the fund itself. In addition, because many types of U.S. government securities trade actively outside the U.S., their prices may rise and fall as changes in global economic conditions affect the demand for these securities.

Dreyfus Government Prime Cash Management

PAST PERFORMANCE

Year-by-year total returns as of 12/31 each year (%)


Best Quarter:	Q3’00	+1.55%
Worst Quarter:	Q2’04	+0.14%

The year-to-date total returns of the fund’s Investor shares as of 3/31/09 was 0.02%.


Average annual total returns
(as of 12/31/08)

1 Year	5 Years	10 Years
1.96%	2.97%	3.13%

Dreyfus Government Prime Cash Management

EXPENSES

As an investor, you pay certain fees and expenses in connection with the fund, which are described in the table below.


Annual fund operating expenses (paid each year as a % of the value of your investment)

Investor Shares
Management fee	0.20%
Rule 12b-1 fee*	0.25%
Other expenses	0.01%
Treasury Guarantee Program fee**	0.02%
Total annual fund operating expenses***	0.48%

*The fee paid to the fund’s distributor for distributing Investor shares, for advertising and marketing related to Investor shares, and for
providing account service and maintenance. Because this fee is paid on an ongoing basis out of fund assets attributable to Investor shares,
over time it will increase the cost of your investment in Investor shares and could cost you more than paying other types of sales charges.
** Reflects the fee paid by the fund to U.S. Treasury Department in connection with the fund’s participation under the Treasury
Department’s Temporary Guarantee Program for Money Market Funds. The fee rate reflects the fund’s participation in the Program,
which terminated on May 1, 2009.
*** For the fiscal year ended January 31, 2009, Dreyfus assumed certain fund expenses pursuant to an agreement in effect, which resulted
in reducing total annual fund operating expenses from 0.48% to 0.47%. This agreement terminates on July 1, 2009.

EXAMPLE


1 Year	3 Years	5 Years	10 Years
$49	$154	$269	$604

MANAGEMENT

FINANCIAL HIGHLIGHTS

These financial highlights describe the performance of the fund’s Investor shares for the fiscal periods indicated. “Total return” shows how much your investment in the fund would have increased (or decreased) during each period, assuming you had reinvested all dividends and distributions. These financial highlights have been audited by Ernst & Young LLP, an independent registered public accounting firm, whose report, along with the fund’s financial statements, is included in the annual report, which is available upon request.


			Year Ended January 31,

Dreyfus Government Cash Management	2009	2008	2007	2006	2005
Per Share Data ($):
Net asset value, beginning of period	1.00	1.00	1.00	1.00	1.00
Investment Operations:
Investment income--net	.017	.046	.046	.029	.010
Distributions:
Dividends from investment income-net	(.017)	(.046)	(.046)	(.029)	(.010)
Net asset value, end of period	1.00	1.00	1.00	1.00	1.00
Total Return (%)	1.76	4.67	4.72	2.97	1.01
Ratios/Supplemental Data (%):
Ratio of total expenses to average net assets	.46	.45	.45	.45	.45
Ratio of net investment income to average net assets	1.39	4.48	4.64	2.90	.95
Net Assets, end of period ($ x 1,000,000)	4,058	1,738	909	1,050	1,287


			Year Ended January 31,
Dreyfus Government Prime Cash
Management	2009	2008	2007	2006	2005
Per Share Data ($):
Net asset value, beginning of period	1.00	1.00	1.00	1.00	1.00
Investment Operations:
Investment income--net	.016	.046	.046	.029	.010
Distributions:
Dividends from investment income--net	(.016)	(.046)	(.046)	(.029)	(.010)
Net asset value, end of period	1.00	1.00	1.00	1.00	1.00
Total Return (%)	1.66	4.65	4.69	2.92	.96
Ratios/Supplemental Data (%):
Ratio of total expenses to average net assets	.47	.45	.45	.45	.45
Ratio of net expenses to average net assets	.47	.45	.45	.45	.45
Ratio of net investment income to average net assets	1.39	4.42	4.61	2.96	.94
Net Assets, end of period ($ x 1,000,000)	1,178	563	275	242	209

Your Investment

SHAREHOLDER GUIDE

Each fund is designed for institutional investors , particularly banks, acting for themselves or in a fiduciary, advisory, agency, custodial or similar capacity. Generally, each investor will be required to open a single master account with the fund for all purposes. In certain cases, the fund may request investors to maintain separate master accounts for shares held by the investor (i) for its own account, for the account of other institutions and for accounts for which the institution acts as a fiduciary, and (ii) for accounts for which the investor acts in some other capacity. An institution may arrange with the fund's transfer agent for sub-accounting services and will be charged directly for the cost of such services. Institutions purchasing Investor shares for the benefit of their clients may impose policies, limitations and fees which are different from those described in this prospectus.

Valuing Shares

Your price for Investor shares is the net asset value per share (NAV).

All times are Eastern time.

How to Buy Shares

For all funds, all times are Eastern time.


Minimum investments

	Initial	Additional
Investor Shares	$10,000,000*	none

* The minimum initial investment in Investor shares is $10,000,000,
unless: (a) the investor has invested at least $10,000,000 in the
aggregate among any Dreyfus Cash Management fund, Dreyfus
Institutional Cash Advantage Fund and Dreyfus Institutional Cash
Advantage Plus Fund (including in any class of a fund); or (b) the
investor has, in the opinion of Dreyfus Cash Investment Services
Division, adequate intent and availability of assets to reach a future
level of investment of $10,000,000 among the funds named above.

How to Sell Shares

You may sell (redeem) shares at any time by wire, telephone, or compatible computer facility. Shares will be sold at the next determined NAV.

For all funds, all times are Eastern time.

Applicable to all funds:

General Policies

Each fund also reserves the right to:

refuse any purchase or exchange request
change or discontinue its exchange privilege, or temporarily suspend the privilege during unusual market conditions
change its minimum investment amounts
“redeem in kind,” or make payments in securities rather than cash, if the amount redeemed is large enough to affect fund operations (for example, if it exceeds 1% of the fund’s assets). Investors are urged to call 1-800- 242-2224 before effecting any large transactions.

Each fund also may process purchase and sale orders and calculate its NAV on days the fund’s primary trading markets are open and the fund’s management determines to do so.

DISTRIBUTIONS AND TAXES

The tax status of any distribution generally is the same regardless of how long you have been in the fund and whether you reinvest your distributions or take them in cash.

The tax status of your distributions will be detailed in your annual tax statement from the fund. Because everyone’s tax situation is unique, please consult your tax adviser before investing.

SERVICES FOR FUND INVESTORS

Account statements

NOTES


Contents


The Funds
Introduction	1
Dreyfus Government Cash Management	2
Dreyfus Government Prime Cash Management	6
Management	10
Financial Highlights	11


Your Investment
Shareholder Guide	12
Distributions and Taxes	15
Services for Fund Investors	16

For More Information

See back cover.

The Funds

Dreyfus Government Cash Management
Dreyfus Government Prime Cash Management

INTRODUCTION

Throughout this prospectus, references to “the fund” apply to all funds, unless otherwise noted.

Dreyfus Government Cash Management

GOAL/APPROACH

Dreyfus Government Cash Management

MAIN RISKS

Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. The fund’s yield will vary; it is not fixed for a specific period like the yield on a bank certificate of deposit. A sharp and unexpected rise in interest rates could cause a money market fund’s share price to drop below a dollar. However, the extremely short maturities of the securities held in money market portfolios - a means of achieving an overall fund objective of principal safety - reduces their potential for price fluctuation.
U.S. Treasury securities risk. A security backed by the U.S. Treasury or the full faith and credit of the United States is guaranteed only as to the timely payment of interest and principal when held to maturity, but the market prices for such securities are not guaranteed and will fluctuate. Because U.S. Treasury securities trade actively outside the United States, their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Government securities risk . Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities of a security held by the fund does not apply to the market value of such security or to shares of the fund itself. In addition, because many types of U.S. government securities trade actively outside the U.S., their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Counterparty risk. The risk that a counterparty in a repurchase agreement could fail to honor the terms of its agreement.

Dreyfus Government Cash Management

PAST PERFORMANCE

The bar chart and table shown illustrate the risks of investing in the fund. The bar chart shows the changes in the performance of the fund’s Participant shares from year to year. The table shows the average annual total returns of the fund’s Participant shares over time. All returns assume reinvestment of dividends and distributions. Of course, past performance (before and after taxes) is no guarantee of future results.

Year-by-year total returns as of 12/31 each year (%)


Best Quarter:	Q3’00	+1.52%
Worst Quarter:	Q2’04	+0.12%

The year-to-date total return of the fund’s Participant shares as of 3/31/09 was 0.04%.


Average annual total returns
(as of 12/31/08)

1 Year	5 Years	10 Years
1.88%	2.86%	3.04%

For the current yield for Participant shares, institutions may call toll-free 1-800-346-3621 . Individuals or entities

for whom institutions may purchase or redeem shares should call the institution directly.

Dreyfus Government Cash Management

EXPENSES

As an investor, you pay certain fees and expenses in connection with the fund, which are described in the table below.


Annual fund operating expenses (paid each year as a % of the value of your investment)

Participant Shares
Management fee	0.20%
Rule 12b-1 fee*	0.40%
Other expenses	0.01%
Treasury Guarantee Program fee**	0.01%
Total annual fund operating expenses***	0.62%

*The fee paid to the fund’s distributor for distributing Participant shares, for advertising and marketing related to Participant shares, and
for providing account service and maintenance. Because this fee is paid on an ongoing basis out of fund assets attributable to Participant
shares, over time it will increase the cost of your investment in Participant shares and could cost you more than paying other types of sales
charges.
** Reflects the fee paid by the fund to U.S. Treasury Department in connection with the fund’s participation under the Treasury
Department’s Temporary Guarantee Program for Money Market Funds. The fee rate reflects the fund’s participation in the Program,
which terminated on May 1, 2009.
*** For the fiscal year ended January 31, 2009, Dreyfus assumed certain fund expenses pursuant to an agreement in effect, which resulted
in reducing total annual fund operating expenses from 0.62% to 0.61%. This agreement terminates on July 1, 2009.

EXAMPLE


1 Year	3 Years	5 Years	10 Years
$63	$199	$346	$774

Dreyfus Government Prime Cash Management

GOAL/APPROACH

Dreyfus Government Prime Cash Management

MAIN RISKS

Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. The fund’s yield will vary; it is not fixed for a specific period like the yield on a bank certificate of deposit. A sharp and unexpected rise in interest rates could cause a money market fund’s share price to drop below a dollar. However, the extremely short maturities of the securities held in money market portfolios - a means of achieving an overall fund objective of principal safety - reduces their potential for price fluctuation.
U.S. Treasury securities risk. A security backed by the U.S. Treasury or the full faith and credit of the United States is guaranteed only as to the timely payment of interest and principal when held to maturity, but the market prices for such securities are not guaranteed and will fluctuate. Because U.S. Treasury securities trade actively outside the United States, their prices may rise and fall as changes in global economic conditions affect the demand for these securities.
Government securities risk . Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities of a security held by the fund does not apply to the market value of such security or to shares of the fund itself. In addition, because many types of U.S. government securities trade actively outside the U.S., their prices may rise and fall as changes in global economic conditions affect the demand for these securities.

Dreyfus Government Prime Cash Management

PAST PERFORMANCE

Year-by-year total returns as of 12/31 each year (%)


Best Quarter:	Q3’00	+1.51%
Worst Quarter:	Q2’04	+0.11%

The year-to-date total returns of the fund’s Participant shares as of 3/31/09 was 0.01%.


Average annual total returns
(as of 12/31/08)

1 Year	5 Years	10 Years
1.81%	2.82%	2.97%

Dreyfus Government Prime Cash Management

EXPENSES

As an investor, you pay certain fees and expenses in connection with the fund, which are described in the table below.


Annual fund operating expenses (paid each year as a % of the value of your investment)

Participant Shares
Management fee	0.20%
Rule 12b-1 fee*	0.40%
Other expenses	0.01%
Treasury Guarantee Program fee**	0.02%
Total annual fund operating expenses***	0.62%

EXAMPLE


1 Year	3 Years	5 Years	10 Years
$63	$199	$346	$774

MANAGEMENT

FINANCIAL HIGHLIGHTS

These financial highlights describe the performance of the fund’s Participant shares for the fiscal periods indicated. “Total return” shows how much your investment in the fund would have increased (or decreased) during each period, assuming you had reinvested all dividends and distributions. These financial highlights have been audited by Ernst & Young LLP, an independent registered public accounting firm, whose report, along with the fund’s financial statements, is included in the annual report, which is available upon request.


			Year Ended January 31,

Dreyfus Government Cash Management	2009	2008	2007	2006	2005
Per Share Data ($):
Net asset value, beginning of period	1.00	1.00	1.00	1.00	1.00
Investment Operations:
Investment income--net	.016	.044	.045	.028	.009
Distributions:
Dividends from investment income-net	(.016)	(.044)	(.045)	(.028)	(.009)
Net asset value, end of period	1.00	1.00	1.00	1.00	1.00
Total Return (%)	1.60	4.51	4.57	2.81	.86
Ratios/Supplemental Data (%):
Ratio of total expenses to average net assets	.61	.60	.60	.60	.60
Ratio of net investment income to average net assets	1.24	4.33	4.49	2.75	.80
Net Assets, end of period ($ x 1,000,000)	662	445	196	244	289


			Year Ended January 31,
Dreyfus Government Prime Cash
Management	2009	2008	2007	2006	2005
Per Share Data ($):
Net asset value, beginning of period	1.00	1.00	1.00	1.00	1.00
Investment Operations:
Investment income--net	.015	.044	.044	.027	.008
Distributions:
Dividends from investment income--net	(.015)	(.044)	(.044)	(.027)	(.008)
Net asset value, end of period	1.00	1.00	1.00	1.00	1.00
Total Return (%)	1.51	4.49	4.53	2.77	.81
Ratios/Supplemental Data (%):
Ratio of total expenses to average net assets	.62	.60	.60	.60	.60
Ratio of net expenses to average net assets	.61	.60	.60	.60	.60
Ratio of net investment income to average net assets	1.25	4.27	4.46	2.81	.79
Net Assets, end of period ($ x 1,000,000)	1,346	711	341	208	230

Your Investment

SHAREHOLDER GUIDE

Each fund is designed for institutional investors , particularly banks, acting for themselves or in a fiduciary, advisory, agency, custodial or similar capacity. Generally, each investor will be required to open a single master account with the fund for all purposes. In certain cases, the fund may request investors to maintain separate master accounts for shares held by the investor (i) for its own account, for the account of other institutions and for accounts for which the institution acts as a fiduciary, and (ii) for accounts for which the investor acts in some other capacity. An institution may arrange with the fund's transfer agent for sub-accounting services and will be charged directly for the cost of such services. Institutions purchasing Participant shares for the benefit of their clients may impose policies, limitations and fees which are different from those described in this prospectus.

Valuing Shares

Your price for Participant shares is the net asset value per share (NAV).

All times are Eastern time.

How to Buy Shares

For all funds, all times are Eastern time.


Minimum investments

	Initial	Additional
Participant Shares	$10,000,000*	none

* The minimum initial investment in Participant shares is $10,000,000,
unless: (a) the investor has invested at least $10,000,000 in the
aggregate among any Dreyfus Cash Management fund, Dreyfus
Institutional Cash Advantage Fund and Dreyfus Institutional Cash
Advantage Plus Fund (including in any class of a fund); or (b) the
investor has, in the opinion of Dreyfus Cash Investment Services
Division, adequate intent and availability of assets to reach a future
level of investment of $10,000,000 among the funds named above.

How to Sell Shares

You may sell (redeem) shares at any time by wire, telephone, or compatible computer facility. Shares will be sold at the next determined NAV.

For all funds, all times are Eastern time.

Applicable to all funds:

General Policies

Each fund also reserves the right to:

refuse any purchase or exchange request
change or discontinue its exchange privilege, or temporarily suspend the privilege during unusual market conditions
change its minimum investment amounts
“redeem in kind,” or make payments in securities rather than cash, if the amount redeemed is large enough to affect fund operations (for example, if it exceeds 1% of the fund’s assets). Investors are urged to call 1-800- 242-2224 before effecting any large transactions.

Each fund also may process purchase and sale orders and calculate its NAV on days the fund’s primary trading markets are open and the fund’s management determines to do so.

DISTRIBUTIONS AND TAXES

The tax status of any distribution generally is the same regardless of how long you have been in the fund and whether you reinvest your distributions or take them in cash.

The tax status of your distributions will be detailed in your annual tax statement from the fund. Because everyone’s tax situation is unique, please consult your tax adviser before investing.

SERVICES FOR FUND INVESTORS

Account statements