Mutual Fund Summary Prospectus (497k)

APRIL 30, 2013

SUMMARY PROSPECTUS

BlackRock Funds II | BlackRock Shares

BlackRock International Bond Portfolio
BlackRock: BIBBX

Before you invest, you may want to review the Fund’s prospectus, which contains more information about the Fund and its risks. You can find the Fund’s prospectus (including amendments and supplements) and other information about the Fund, including the Fund’s statement of additional information and shareholder report, online at http://www.blackrock.com/prospectus. You can also get this information at no cost by calling (800) 441-7762 or by sending an e-mail request to prospectus.request@blackrock.com , or from your financial professional. The Fund’s prospectus and statement of additional information, both dated April 30, 2013, as amended and supplemented from time to time, are incorporated by reference into (legally made a part of) this Summary Prospectus.

This Summary Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the adequacy of this Summary Prospectus. Any representation to the contrary is a criminal offense.

Not FDIC Insured • No Bank Guarantee • May Lose Value

Summary Prospectus

Key Facts about BlackRock International Bond Portfolio

Investment Objective

The BlackRock International Bond Portfolio (“International Bond Portfolio” or the “Fund”) seeks to maximize total return, consistent with income generation and prudent investment management.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)	BlackRock Shares
Management Fee		0.55	%
Distribution and/or Service (12b-1) Fees	None
Other Expenses		0.21	%
Total Annual Fund Operating Expenses		0.76	%
Fee Waivers and/or Expense Reimbursements ¹	None
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements ¹		0.76	%

As described in the “Management of the Funds” section on page 33, BlackRock has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 0.79% of average daily net assets until May 1, 2014. The Fund may have to repay some of these waivers and reimbursements to BlackRock in the following two years. The contractual agreement may be terminated upon 90 days notice by a majority of the non-interested trustees of the Fund or by a vote of a majority of the outstanding voting securities of the Fund.

Example:

This Example 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 and then redeem all of your shares at the end of those periods. 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
BlackRock Shares				$	78			$	243			$	422			$	942

Portfolio Turnover:

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 64% of the average value of its portfolio.

Principal Investment Strategies of the Fund

The International Bond Portfolio invests primarily in non-dollar denominated bonds of issuers located outside of the United States. The Fund normally invests at least 80% of its assets in bonds and at least 65% of its assets in bonds of a diversified group of non-U.S. issuers from at least three developed countries. The Fund may invest more than 25% of its assets in the securities of issuers located in Canada, France, Germany, Japan and the United Kingdom. The Fund may from time to time invest in investment grade bonds of issuers in emerging market countries. The Fund will also invest in non-U.S. currencies, and the Fund may underweight or overweight a currency based on the Fund management

team’s outlook. The Fund may only buy securities rated investment grade at the time of purchase by at least one major rating agency or determined by the management team to be of similar quality. Split rated bonds will be considered to have the higher credit rating.

The Fund considers non-U.S. issuers to include (i) foreign government issuers, (ii) issuers organized or located outside the U.S., (iii) issuers which primarily trade in a market located outside the U.S., or (iv) issuers doing a substantial amount of business outside the U.S., which the Fund considers to be companies that derive at least 50% of their revenue or profits from business outside the U.S. or have at least 50% of their sales or assets outside the U.S. The Fund will allocate its assets among various regions and countries (but in no less than three different countries). For temporary defensive purposes the Fund may deviate very substantially from the allocation described above.

The management team will normally attempt to structure the Fund’s portfolio to have comparable duration to its benchmark.

The management team may, when consistent with the Fund’s investment objective, buy or sell options or futures, or enter into credit default swaps and interest rate or foreign currency transactions, including swaps (collectively, commonly known as derivatives). The Fund typically uses derivatives as a substitute for taking a position in the underlying asset and/or as part of a strategy designed to reduce exposure to other risks, such as interest rate or currency risk. The Fund may also use derivatives to enhance returns, in which case their use would involve leveraging risk. The Fund may seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as reverse repurchase agreements or dollar rolls, which involves a sale by a fund of a mortgage-backed or other security concurrently with an agreement by the fund to repurchase a similar security at a later date at an agreed-upon price).

Principal Risks of Investing in the Fund

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. The following is a summary description of principal risks of investing in the Fund.

Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer.

Derivatives Risk — The Fund’s use of derivatives may reduce the Fund’s returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. Valuation may be more difficult in times of market turmoil since many investors and market makers may be reluctant to purchase complex instruments or quote prices for them. Derivatives also may expose the Fund to greater risk and increase its costs. Certain transactions in derivatives involve substantial leverage risk and may expose the Fund to potential losses that exceed the amount originally invested by the Fund. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation is not yet known and may not be known for some time. New regulation may make derivatives more costly, may limit the availability of derivatives, or may otherwise adversely affect the value or performance of derivatives.

Emerging Markets Risk — Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyperinflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

Extension Risk — When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

Foreign Securities Risk — Foreign investments often involve special risks not present in U.S. investments that can increase the chances that the Fund will lose money. These risks include:

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The Fund generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

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Changes in foreign currency exchange rates can affect the value of the Fund’s portfolio.

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The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

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The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

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Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

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Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

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The European financial markets have recently experienced volatility and adverse trends due to concerns about economic downturns in, or rising government debt levels of, several European countries. These events may spread to other countries in Europe, including countries that do not use the Euro. These events may affect the value and liquidity of certain of the Fund’s investments.

Interest Rate Risk — Interest rate risk is the risk that prices of bonds and other fixed-income securities will increase as interest rates fall, and decrease as interest rates rise.

Leverage Risk — Some transactions may give rise to a form of economic leverage. These transactions may include, among others, derivatives, and may expose the Fund to greater risk and increase its costs. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet any required asset segregation requirements. Increases and decreases in the value of the Fund’s portfolio will be magnified when the Fund uses leverage.

Liquidity Risk — Liquidity risk exists when particular investments are difficult to purchase or sell. The Fund’s investments in illiquid securities may reduce the returns of the Fund because it may be difficult to sell the illiquid securities at an advantageous time or price. To the extent that the Fund’s principal investment strategies involve derivatives or securities with substantial market and/or credit risk, the Fund will tend to have the greatest exposure to liquidity risk. Liquid investments may become illiquid after purchase by the Fund, particularly during periods of market turmoil. Illiquid investments may be harder to value, especially in changing markets, and if the Fund is forced to sell these investments to meet redemption requests or for other cash needs, the Fund may suffer a loss. In addition, when there is illiquidity in the market for certain securities, the Fund, due to limitations on illiquid investments, may be subject to purchase and sale restrictions.

Market Risk and Selection Risk — Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by Fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

Prepayment Risk — When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields.

Risks of Concentrating in One Country — Investing a significant portion of assets in one country makes the Fund more dependent upon the political and economic circumstances of that particular country than a mutual fund that is more widely diversified.

Sovereign Debt Risk — Sovereign debt instruments are subject to the risk that a governmental entity may delay or refuse to pay interest or repay principal on its sovereign debt, due, for example, to cash flow problems, insufficient foreign currency reserves, political considerations, the relative size of the governmental entity’s debt position in relation to the economy or the failure to put in place economic reforms required by the International Monetary Fund or other multilateral agencies.

Performance Information

The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. The table compares the Fund’s performance to that of the Citigroup Non-U.S. Dollar World Government Bond Index. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If the Fund’s investment manager and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund’s returns would have been lower. Updated information on the Fund’s performance can be obtained by visiting http://www.blackrock.com/funds or can be obtained by phone at 800-882-0052.

BlackRock Shares
ANNUAL TOTAL RETURNS
International Bond Portfolio
As of 12/31

During the ten-year period shown in the bar chart, the highest return for a quarter was 10.77% (quarter ended September 30, 2010) and the lowest return for a quarter was –6.01% (quarter ended September 30, 2008). The year-to-date return as of March 31, 2013 was -3.85%.

As of 12/31/12 Average Annual Total Returns	1 Year	5 Years	10 Years
BlackRock International Bond Portfolio — BlackRock Shares
Return Before Taxes	3.17%	4.08%	5.25%
Return After Taxes on Distributions	0.99%	1.49%	3.47%
Return After Taxes on Distributions and Sale of Shares	2.07%	1.95%	3.48%
Citigroup Non-U.S. Dollar World Government Bond Index (Reflects no deduction for fees, expenses or taxes)	1.51%	5.24%	6.38%

After-tax returns are calculated using the historical highest individual Federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

Investment Manager

The Fund’s investment manager is BlackRock Advisors, LLC (“BlackRock”). The Fund’s sub-advisers are BlackRock Financial Management, Inc. and BlackRock International Limited. Where applicable, the use of the term BlackRock also refers to the Fund’s sub-advisers.

Portfolio Managers

Name				Portfolio Manager of the Fund Since				Title
Scott Thiel				2011				Managing Director of BlackRock, Inc.

Purchase and Sale of Fund Shares

You may purchase or redeem shares of the Fund each day the New York Stock Exchange (“NYSE”) is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at (800) 537-4942, by mail (c/o BlackRock Funds, P.O. Box 9819, Providence, Rhode Island 02940-8019), or by the Internet at www.blackrock.com/funds. The Fund’s initial and subsequent investment minimums generally are as follows, although the Fund may reduce or waive the minimums in some cases:

				BlackRock Shares
Minimum Initial Investment				· $5,000,000 for institutions and individuals; · There is no minimum initial investment requirement for fee-based programs with an annual fee of at least 0.50% or certain employer-sponsored retirement plans; · BlackRock Shares are available to clients of registered investment advisers who have $250,000 invested in the Fund.
Minimum Additional Investment				There is no minimum amount for additional investments.

Tax Information

The Fund’s dividends and distributions may be subject to Federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to Federal income tax upon withdrawal from such tax deferred arrangements.

Payments to Broker/Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and BlackRock Investments, LLC, the Fund’s distributor, or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary’s website for more information.