MET INVESTORS SERIES    TRUST SUMMARY PROSPECTUS    April 23, 2012

Invesco Balanced-Risk Allocation Portfolio

Class B Shares

Before you invest, you may want to review the Portfolio’s Prospectus, which contains more information about the Portfolio and its risks. You can find the Portfolio’s Prospectus and other information about the Portfolio (including the documents listed below) online at www.metlife.com/variablefunds. You can also get this information at no cost by calling 1-800-638-7732 or by sending an e-mail request to RCG@metlife.com. The Portfolio’s Prospectus and Statement of Additional Information, both dated April 23, 2012, are both incorporated by reference into this Summary Prospectus. This Summary Prospectus is intended for individuals who have purchased certain variable life insurance policies and variable annuity contracts (collectively, “Contracts”) from Metropolitan Life Insurance Company and its affiliates and is not intended for use by other investors.

Investment Objective

Seeks total return.

Fees and Expenses of the Portfolio

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. These fees and expenses are estimated for the period ended December 31, 2012, and are expressed as a percentage of the Portfolio’s average daily net assets over that period. The table and the Example below do not reflect the fees, expenses or withdrawal charges imposed by the Contracts. If Contract expenses were reflected, the fees and expenses in the table and Example would be higher. See the Contract prospectus for a description of those fees, expenses and charges.

Shareholder Fees (fees paid directly from your investment)—None

Annual Portfolio Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

	Class B
Management Fee	0.66%
Distribution and/or Service (12b-1) Fees	0.25%
Other Expenses*	0.15%
Acquired Fund Fees and Expenses*	0.10%
Total Annual Portfolio Operating Expenses and Acquired Fund Fees and Expenses	1.16%
* Other Expenses and Acquired Fund Fees and Expenses are based on estimated amounts for the current fiscal year.

Example

The following Example is intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Portfolio 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, that you reinvest all of your dividends, and that the Portfolio’s operating expenses remain the same.

Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

	Class B
1 Year	$119
3 Years	$370

Portfolio Turnover

The Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual portfolio operating expenses or in the Example, affect the Portfolio’s performance. While the Portfolio has not commenced operations as of the date of this Prospectus, it is anticipated that the Portfolio’s turnover rate will typically exceed 100%.

Principal Investment Strategies

Under normal market conditions, the Portfolio’s subadviser, Invesco Advisers, Inc. (“Invesco”), will invest the Portfolio’s assets in derivatives and other financially-linked instruments the performance of which is expected to correspond to U.S. and international fixed income, equity and commodity markets. The Portfolio may invest in derivatives and other financially-linked instruments, and may also invest in U.S. and foreign government debt securities and other securities such as investment companies that include money market funds and exchange-traded funds (“ETFs”), and commodity-linked notes. The Portfolio’s international investments will generally be in developed countries, but may also include emerging market countries. The Portfolio’s fixed income investments will generally be investment grade, while the Portfolio’s commodity markets exposure will generally be to the precious metals, agriculture, energy and industrial metals sectors.

Generally, the Portfolio invests in many types of investment instruments the performance of which is expected to correspond to global fixed income, equity and commodity markets, including, but not limited to: equity index futures, swaps on equity index futures, total return swaps, commodity futures, swaps on

commodity futures, bond futures, swaps on bond futures, government bonds, and cash and cash equivalents including, but not limited to, money market fund shares, either by investing directly in such instruments, or indirectly by investing in a subsidiary as discussed below. Futures contracts are standardized agreements to buy or sell a particular currency, commodity or financial instrument at a pre-determined price at a future date, while swap agreements are derivative instruments through which counterparties exchange cash flows of one instrument for those of another instrument. While the Portfolio normally does not engage in borrowing, leverage will be created when the Portfolio engages in futures transactions or uses certain other derivative instruments.

The Portfolio’s investments in certain derivatives may create significant leveraged exposure to certain equity, fixed income and commodity markets. Financial leverage magnifies exposure to the swings in prices of an asset class underlying a derivative instrument and may result in increased volatility, which means the Portfolio will have the potential for greater gains, as well as the potential for greater losses, than if the Portfolio does not use derivatives that have a leveraging effect. There is no assurance that the Portfolio’s use of derivative instruments providing leveraged exposure will enable the Portfolio to achieve its investment objective. The Investment Company Act of 1940, as amended (the “1940 Act”), and the rules and interpretations thereunder impose certain limitations on the Portfolio’s ability to use leverage.

The Portfolio may invest up to 25% of its total assets in a wholly-owned and controlled subsidiary of the Portfolio, organized under the laws of the Cayman Islands as an exempted company (the “Subsidiary”). The Subsidiary is advised by Invesco and has the same investment objective as the Portfolio. Generally, the Subsidiary will invest primarily in commodity derivatives, exchange-traded notes (“ETNs”), cash and cash equivalents, including money market funds affiliated with Invesco. The Portfolio will invest in the Subsidiary and ETFs in order to gain exposure to the commodities markets within the limitations of the federal tax laws, rules and regulations that apply to registered investment companies. The Subsidiary, in turn, will invest in futures, ETNs and other securities and financially-linked instruments. Unlike the Portfolio, the Subsidiary may invest without limitation in commodity-linked derivatives; however, the Subsidiary will comply with the same 1940 Act asset coverage requirements with respect to its investments in commodity-linked derivatives that are applicable to the Portfolio’s transactions in derivatives. In addition, to the extent applicable to the investment activities of the Subsidiary, the Subsidiary will be subject to the same fundamental investment restrictions and will follow the same compliance policies and procedures as the Portfolio. The Portfolio is the sole shareholder of the Subsidiary and does not expect shares of the Subsidiary to be offered or sold to other investors.

The Portfolio will generally maintain 60% of its total assets in cash and cash equivalent instruments, including money market funds affiliated with Invesco. Some of the cash holdings will serve as margin or collateral for the Portfolio’s obligations under derivative transactions and also earn income for the Portfolio. A significant portion of the cash and cash equivalent assets of the Portfolio may be invested directly or indirectly in money market instruments, which may include, but are not limited to, U.S. Government securities, U.S. Government agency securities, Eurodollar obligations, bankers’ acceptances, short-term fixed income securities, overnight and/or fixed term repurchase agreements, money market fund shares, and cash and cash equivalents with one year or less term to maturity.

The Portfolio is non-diversified, which means that it can hold securities of a smaller number of issuers and can invest a larger percentage of its assets in a single issuer than a diversified portfolio.

The Portfolio and the Subsidiary employ a risk management strategy to help minimize loss of capital and reduce excessive volatility. Relative to traditional balanced portfolios, the Portfolio will seek to provide greater capital loss protection during down markets. The Portfolio’s management team will seek to accomplish this through a three-step investment process involving (1) asset selection, (2) portfolio construction and (3) active positioning.

The first step involves asset selection. The management team begins the process by selecting representative assets to gain exposure to equity, fixed income and commodity markets from a universe of over fifty assets. The selection process first evaluates a particular asset’s theoretical case for long-term excess returns relative to cash. The identified assets are then screened to meet minimum liquidity criteria. Finally, the team reviews the expected correlation among the assets and the expected risk for each asset to determine whether the selected assets are likely to improve the expected risk adjusted return of the Portfolio.

The second step involves portfolio construction. Proprietary estimates for risk and correlation are used by the management team to create a portfolio. The team re-estimates the risk contributed by each asset and re-optimizes the portfolio periodically or when new assets are introduced to the Portfolio.

The final step involves active positioning. The management team actively adjusts portfolio positions to reflect the near-term market environment, while remaining consistent with the optimized long-term portfolio structure described in step two above. The management team balances these two competing ideas—opportunity for excess return from active positioning and the need to maintain asset class exposure set forth in the optimized portfolio structure—by setting controlled tactical ranges around the long-term asset allocation. The tactical ranges differ for each asset based on the management team’s estimates of the asset’s volatility. The resulting asset allocation is then implemented by investing in derivatives, other financially-linked instruments, U.S. and foreign government debt securities, other securities, and cash and cash equivalent instruments, including affiliated money market funds. By using derivatives, the Portfolio is able to gain greater exposure to assets within each class than would be possible by investing directly in securities or other assets, and thus seeks to balance the amount of risk each asset class contributes to the portfolio.

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Although Invesco will target a specified volatility level for the Portfolio, the Portfolio’s net asset value (“NAV”) may be volatile over short-term periods because of the significant use of derivatives that have a leveraging effect. Volatility is a statistical measurement of the magnitude of up and down fluctuations in the value of a financial instrument or index over time. Volatility may result from rapid and dramatic price swings. Invesco normally will target an annualized volatility level for the Portfolio of 8%, but allows for volatility to drift between a lower (6%) and upper (10%) band. Actual or realized volatility can and will differ from the target volatility. Although an annualized volatility level of 8% is normally targeted for the Portfolio, Invesco may, under certain market conditions, target a lower volatility level for the Portfolio.

Primary Risks

As with all mutual funds, there is no guarantee that the Portfolio will achieve its investment objective. You could lose money by investing in the Portfolio. An investment in the Portfolio through a Contract is not a deposit or obligation of, or guaranteed by, any bank, and is not federally insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board, or any other agency of the U.S. Government.

The value of your investment in the Portfolio may be affected by one or more of the following risks, which are described in more detail in “Primary Risks of Investing in the Portfolio” in the Prospectus, any of which could cause the Portfolio’s return, the price of the Portfolio’s shares or the Portfolio’s yield to fluctuate. Please note that there are many other circumstances that could adversely affect your investment and prevent the Portfolio from reaching its objective, which are not described here. In addition, there can be no assurance that employing a “risk balanced” approach will achieve any particular level or return or will, in fact, reduce volatility or potential loss.

Market Risk.    The Portfolio’s share price can fall because of, among other things, a decline in the market as a whole, deterioration in the prospects for a particular industry or company, or changes in general economic conditions, such as prevailing interest rates and investor sentiment. Significant disruptions to the financial markets could adversely affect the liquidity and volatility of securities held by the Portfolio.

Interest Rate Risk.    The value of the Portfolio’s investments in fixed income securities may decline when prevailing interest rates rise or increase when interest rates go down. The longer a security’s maturity or duration, the greater its value will change in response to changes in interest rates. The interest earned on the Portfolio’s investments in fixed income securities may decline when prevailing interest rates decline.

Commodities Risk.    Exposure to the commodities markets may subject the Portfolio to greater volatility than investments in traditional securities. The value of commodity-linked derivative instruments may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity.

Credit and Counterparty Risk.    The value of the Portfolio’s investments may be adversely affected if a security’s credit rating is downgraded; an issuer of an investment held by the Portfolio fails to pay an obligation on a timely basis, otherwise defaults or is perceived by other investors to be less creditworthy; or a counterparty to a derivatives or other transaction with the Portfolio files for bankruptcy, becomes insolvent, or otherwise becomes unable or unwilling to honor its obligation to the Portfolio.

Derivatives Risk.    The Portfolio will primarily invest in derivatives, such as futures contracts and swaps, to seek exposure to certain asset classes and enhance returns. To a lesser extent, the Portfolio may also invest in derivatives to “hedge” or protect its assets from an unfavorable shift in the value or rate of a reference instrument. Derivatives can significantly increase the Portfolio’s exposure to market risk, credit and counterparty risk and other risks, as well as increase transaction costs. Derivatives may be illiquid and difficult to value. Because of their complex nature, some derivatives may not perform as intended. As a result, the Portfolio may not realize the anticipated benefits from a derivative it holds or it may realize losses. A risk of the Portfolio’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

Investment Company and Exchange Traded Fund Risk.    An investment in an investment company or ETF involves substantially the same risks as investing directly in the underlying securities. An investment company or ETF may not achieve its investment objective or execute its investment strategy effectively, which may adversely affect the Portfolio’s performance. The Portfolio must pay its pro rata portion of an investment company’s or ETF’s fees and expenses. Shares of a closed-end investment company or ETF may trade at a premium or discount to the net asset value of its portfolio securities.

Leveraging Risk.    Derivatives and other transactions that give rise to leverage may cause the Portfolio’s performance to be more volatile than if the Portfolio had not been leveraged. Leveraging also may require that the Portfolio liquidate portfolio securities when it may not be advantageous to do so to satisfy its obligations or to meet segregation requirements. Leveraging may expose the Portfolio to losses in excess of the amounts invested or borrowed.

Forward and Futures Contract Risk.    The successful use of forward and futures contracts will depend upon the Subadviser’s skill and experience with respect to such instruments and are subject to special risk considerations. The primary risks associated with the use of forward and futures contracts are (i) the imperfect correlation between the change in market value of the instruments held by the Portfolio and the price of the forward or futures contract; (ii) possible lack of a liquid secondary market for a forward or futures contract and the resulting inability to close a forward or futures contract when desired; (iii) losses caused by unanticipated market movements, which are potentially unlimited; (iv) the Subadviser’s inability to predict correctly the direction of securities prices, interest rates, currency exchange rates and other economic factors; (v) the possibility that the counterparty will

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default in the performance of its obligations; and (vi) if the Portfolio has insufficient cash, it may have to sell securities to meet daily variation margin requirements, and the Portfolio may have to sell securities at a time when it may be disadvantageous to do so.

Foreign Investment Risk.    Investments in foreign securities tend to be more volatile and less liquid than investments in U.S. securities because, among other things, they involve risks relating to political, social and economic developments abroad, as well as risks resulting from differences between the regulations and reporting standards and practices to which U.S. and foreign issuers are subject. To the extent foreign securities are denominated in foreign currencies, their values may be adversely affected by changes in currency exchange rates. All of the risks of investing in foreign securities are typically increased by investing in emerging market countries.

Non-diversification Risk.    To the extent that the Portfolio holds securities of a smaller number of issuers or invests a larger percentage of its assets in a single issuer than a diversified portfolio, the value of the Portfolio, as compared to the value of a diversified portfolio, will generally be more volatile and more sensitive to the performance of any one of those issuers and to economic, political, market or regulatory events affecting any one of those issuers.

Focused Investment Risk.    Substantial investments in a particular market, industry, group of industries, country, region, group of countries, asset class or sector make the Portfolio’s performance more susceptible to any single economic, market, political or regulatory occurrence affecting that particular market, industry, group of industries, country, region, group of countries, asset class or sector than a portfolio that invests more broadly.

Asset Allocation Risk.    The Portfolio’s ability to achieve its investment objective depends upon Invesco’s analysis of various factors and Invesco’s ability to select the appropriate mix of asset classes based on its analysis of such factors, which may prove incorrect. The Portfolio may experience losses or poor relative performance if Invesco allocates a significant portion of the Portfolio’s assets to an asset class that does not perform as Invesco anticipated, including relative to other asset classes. The Portfolio may underperform funds that allocate their assets differently than the Portfolio.

Subsidiary Risk.    By investing in the Subsidiary, the Portfolio is indirectly exposed to the commodities risks associated with the Subsidiary’s investments in commodity-related instruments. There can be no assurance that the Subsidiary’s investments will contribute to the Portfolio’s returns. The Subsidiary is not registered under the 1940 Act and is not subject to all the investor protections of the 1940 Act. Changes in the laws of the United States and/or the Cayman Islands could result in the inability of the Portfolio and/or the Subsidiary to operate as described in this Prospectus and could adversely affect the Portfolio, such as by reducing the Portfolio’s investment returns.

Tax Risk.    In order for the Portfolio to qualify as a regulated investment company under Subchapter M of the Internal Revenue Code of 1986, as amended (the “Code”), the Portfolio must derive at least 90% of its gross income each taxable year from qualifying income, which is described in more detail in the Statement of Additional Information. Because income from certain commodity-linked derivative instruments generally is not considered to be qualifying income, the Portfolio does not generally expect to invest directly in such instruments. Rather, the Portfolio’s investment in the Subsidiary is expected to provide the Portfolio with exposure to the commodities markets within the limitations of the federal tax requirements of Subchapter M. The Portfolio has obtained an opinion from legal counsel to the effect that the annual net profit, if any, realized by the Subsidiary and imputed for income tax purposes to the Portfolio should constitute “qualifying income” for the purposes of the Portfolio remaining qualified as a regulated investment company for U.S. federal income tax purposes. It is possible that the Internal Revenue Service or a court could disagree with the legal opinion obtained by the Portfolio.

Portfolio Turnover Risk.    The investment techniques and strategies utilized by the Portfolio might result in a high degree of portfolio turnover. High portfolio turnover rates will increase the Portfolio’s transaction costs, which can adversely affect the Portfolio’s performance.

Past Performance

As of the date of this Prospectus, the Portfolio had not commenced operations. No performance information is currently available. For information on Invesco’s prior performance with comparable funds, please see “Additional Information about Management—The Subadviser” in the Prospectus.

Management

Adviser.    MetLife Advisers, LLC (“MetLife Advisers”) is the Portfolio’s investment adviser.

Subadviser.    Invesco Advisers, Inc. (the “Subadviser”) is the subadviser to the Portfolio.

Portfolio Managers.    Mark Ahnrud, Portfolio Manager, Chris Devine, Portfolio Manager, Scott Hixon, Portfolio Manager and Head of Investment Research, Christian Ulrich, Portfolio Manager, and Scott Wolle, Chief Investment Officer, all with the Subadviser, have managed the Portfolio since inception.

Tax Information

For information regarding the tax consequences of Contract ownership, please see the prospectus for the relevant Contract.

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Payments to Insurance Companies and Their Affiliates

The Portfolio is not sold directly to the general public but instead is offered as an underlying investment option for Contracts issued by insurance companies that are affiliated with the Portfolio and MetLife Advisers. As a result of these affiliations, the insurance companies may benefit more from offering the Portfolio as an investment option in the Contracts than offering other unaffiliated portfolios. The Portfolio and its related companies may also make payments to the sponsoring insurance companies (or their affiliates) for distribution and/or other services. The benefits to the insurance companies of offering the Portfolio over unaffiliated portfolios and these payments may be factors that the insurance companies consider in including the Portfolio as an underlying investment option in the Contracts and may create a conflict of interest. The prospectus for your Contract contains additional information about these payments.

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