UNITED STATES 

SECURITIES AND EXCHANGE COMMISSION 

Washington, D.C. 20549 

FORM N-CSR 

CERTIFIED SHAREHOLDER REPORT OF REGISTERED 

MANAGEMENT INVESTMENT COMPANIES 

Investment Company Act File Number: 811-5986

T. Rowe Price Index Trust, Inc.

(Exact name of registrant as specified in charter) 

100 East Pratt Street, Baltimore, MD 21202 

(Address of principal executive offices) 

David Oestreicher 

 100 East Pratt Street, Baltimore, MD 21202 

 (Name and address of agent for service) 

Registrant’s telephone number, including area code: (410) 345-2000 

Date of fiscal year end: December 31 

Date of reporting period: June 30, 2011 

Item 1: Report to Shareholders

 Extended Equity Market Index Fund June 30, 2011 

The views and opinions in this report were current as of June 30, 2011. They are not guarantees of performance or investment results and should not be taken as investment advice. Investment decisions reflect a variety of factors, and the managers reserve the right to change their views about individual stocks, sectors, and the markets at any time. As a result, the views expressed should not be relied upon as a forecast of the fund’s future investment intent. The report is certified under the Sarbanes-Oxley Act, which requires mutual funds and other public companies to affirm that, to the best of their knowledge, the information in their financial reports is fairly and accurately stated in all material respects.

REPORTS ON THE WEB

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Manager’s Letter

Fellow Shareholders

U.S. stocks rose strongly at the start of 2011 but pared some of their early gains as weakening economic growth at home and geopolitical instability weighed on investor sentiment. The Equity Index 500 Fund, the Total Equity Market Index Fund, and the Extended Equity Market Index Fund all posted solid gains over the six-month period, broadly tracking the returns of their respective benchmarks.

MARKET ENVIRONMENT

U.S. stocks produced modest gains in the first half of 2011, as strong returns through April were tempered by weakness in the last two months of the period. Equities advanced early on as the economy appeared to strengthen and the Federal Reserve implemented a second round of monetary stimulus to boost economic growth. Corporate earnings were generally robust and private employers added to payrolls in the spring, which helped whittle down a high jobless rate. The S&P 500 Index rose to its highest level in nearly three years on April 29, as optimism about the recovery overcame unrest in the Middle East and North Africa, a spike in oil prices, and a catastrophic earthquake and tsunami in Japan. However, a batch of mixed data at the end of the period raised worries that the recovery was stalling. Jobs growth in May and June was surprisingly weak, pushing the nation’s unemployment rate to 9.2%. In June, the Federal Reserve downgraded its forecast for economic and jobs growth for this year and next, citing financials sector weakness, problems in the housing sector, and other factors. News about Greece’s ballooning debt and its efforts to avoid a default also unnerved global sentiment.

Smaller-cap companies turned in better performance than larger stocks, while growth stocks fared better than value across all market capitalizations. The large-cap S&P 500 Index gained 6.02%, while the S&P Completion Index, a broad measure of small- and mid-cap stock performance, returned 7.45%. All sectors within the S&P 500 rose, except for financials. Defensive sectors outpaced more cyclical areas as investors sought safety in companies that tend to be resilient performers in a weak economy.

SUMMARY OF INVESTMENT STRATEGIES

T. Rowe Price’s equity market index funds are designed for investors who want to harness the potential for long-term capital appreciation from broad exposure to large-cap stocks (Equity Index 500 Fund), small- and mid-cap stocks (Extended Equity Market Index Fund), or the entire U.S. stock market (Total Equity Market Index Fund). These funds could serve as core holdings in an investor’s portfolio, because they offer attributes that many investors will find appealing.

• They are well diversified, which can reduce the potentially negative impact of a given stock on the entire portfolio. The Equity Index 500 Fund invests in all S&P 500 Index stocks, while the Total Equity Market Index Fund and the Extended Equity Market Index Fund invested in approximately 1,406 and 1,720 stocks, respectively, as of June 30, 2011. (Diversification cannot assure a profit or protect against loss in a declining market.)

• They tend to closely track their benchmarks. The Equity Index 500 Fund uses a full replication strategy so that the weightings of our holdings match those of the S&P 500 Index. The Total Equity Market Index Fund and the Extended Equity Market Index Fund use a sampling strategy to approximate the sector allocations, price/earnings ratio, and other attributes of their benchmarks. We occasionally invest in securities such as futures and exchange-traded funds so that the index funds can accommodate cash flows and remain fully invested.

• They offer instant, broad exposure to different sectors of the stock market, and each fund’s sector allocations are consistent with its benchmark’s sector breakdown. As such, changes in the funds’ sector diversification and other overall characteristics reflect changes in the composition of the indexes, rather than strategic shifts that are typical of an actively managed fund.

• Their expenses are generally low, which enables investors to retain more of their returns.

Equity Index 500 Fund
Your fund returned 5.89% in the six-month period ended June 30, 2011, versus 6.02% for the S&P 500 Index. Fund performance tends to slightly lag that of the benchmark due to operating and management expenses.

Nine of the 10 sectors in the S&P 500 ended the reporting period in positive territory. Health care was the top-performing sector, followed by energy. Utilities, consumer discretionary, industrials and business services, consumer staples, and telecommunication services all outperformed the index, while materials and information technology shares trailed with more modest gains. The financials sector was the only negative performer in the index.

Health care, which composed about 11.7% of the fund, outpaced other sectors as investors gained clarity about the impact of health care reform. Companies benefited from robust corporate earnings and held up well in the weak recovery. Leaders included pharmaceutical companies Johnson & Johnson and Pfizer, whose shares rallied after the company’s chief executive officer announced plans to divest non-core businesses to focus on drug development, leading investors to anticipate benefits from asset sales and spinoffs. UnitedHealth Group was another robust performer as its shares rose on strong earnings backed by growing revenue and increased enrollment. Increased health care utilization under the new health care reform plan and the introduction of new drugs are expected to underpin earnings growth in the sector. (Please refer to the fund’s portfolio of investments for a complete list of holdings and the amount each represents in the portfolio.)

The energy sector, which accounts for about 12.7% of the fund, largely recovered from last year’s Gulf of Mexico oil spill. It benefited from higher oil prices as antigovernment protests flared across the Middle East and North Africa earlier this year. Stocks pared gains as oil prices retreated in May and June. The oil, gas, and consumable fuels industry was particularly strong, led by ExxonMobil, Chevron, and Marathon Oil.

Utilities, consumer discretionary, industrials and business services, consumer staples, and telecommunication services all exceeded returns of the broad market, finishing the period with gains of about 7% to 9%. Notable contributors among these sectors included cable providers Comcast and Cablevision, diversified industrial manufacturer United Technologies, tobacco company Philip Morris International, and Internet retailer Amazon.com.

Materials and information technology underperformed the broad index but managed to produce small gains. Information technology represented about 17.8% of the fund and was the largest single sector weighting at the end of the period. Major holdings included IBM, Apple, and Qualcomm. The financials sector returned -3.1% in the index. Its large representation in the index and the fund weighed on overall results. Regulatory concerns, ongoing problems in the housing sector, weak loan demand, and persistently low interest rates continue to overshadow the sector.

Standard & Poor’s authorized 10 changes to the composition of the S&P 500 Index during the first half of 2011. Please see the table on page 10 for a complete list of index changes.

Total Equity Market Index Fund
Your fund returned 5.99% for the six-month period ended June 30, 2011, closely tracking the 6.28% return of its benchmark, the S&P Total Market Index. Fund performance often slightly trails that of the benchmark due to operating and management expenses.

The S&P Total Market Index, which represents the entire U.S. stock market, includes all S&P 500 companies. Stocks of the S&P 500 represent over 75% of the S&P Total Market Index’s overall market value. As with the S&P 500, the largest holdings of the S&P Total Market Index have the greatest influence on the fund’s performance. In addition, the weightings of the major sectors are broadly similar between the two benchmarks.

As with the S&P 500 Index, health care was the strongest-performing sector of the S&P Total Market Index during the period. Energy followed suit amid higher oil prices, and utilities gained as investors flocked to relatively defensive sectors. Consumer staples, consumer discretionary, industrials and business services, and telecommunication services posted solid returns. Materials and information technology shares produced modest gains but trailed the index, while financials once again was the sole sector with negative returns.

Extended Equity Market Index Fund
Your fund returned 7.39% for the six-month period ended June 30, 2011, versus 7.45% for the S&P Completion Index. Fund performance tends to differ slightly from that of the benchmark due to the fund’s operating and management expenses.

All 10 sectors in the small- and mid-cap segment of the market posted positive results for the last six months. Consumer staples was by far the best-performing sector, posting an impressive 21.61% return in the index. Health care, energy, and utilities also enjoyed double-digit returns, while the materials and consumer discretionary sectors slightly outperformed the index. Telecommunication services, information technology, and industrials and business services trailed the index due to the weakening economic recovery. Smaller-cap financials also underperformed but eked out a small gain in contrast to their larger-cap peers.

OUTLOOK

Optimism about a strong recovery has diminished since the start of the year, but we expect the U.S. economy will continue to gradually strengthen for the rest of 2011. We believe stock market volatility will be heightened in the coming months as the economy slowly picks up. U.S. companies are in very good financial shape, earnings and balance sheets are solid, and stock valuations appear reasonable—all of which should limit the stock market’s downside risk should the economy fall into another downturn. The relatively weak U.S. dollar, while problematic in the long run, should continue to benefit U.S. exports and make domestic companies more competitive globally.

Having said that, the housing and job markets remain in poor shape, and we don’t anticipate significant improvement in either until 2012. Overseas, the risk of a wider European debt crisis due to a possible Greek default continues to unnerve investors. Despite these near-term risks, we believe that solid fundamentals should provide ample investment opportunities as the economy recovers. Many stocks are trading at attractive levels, even assuming conservative growth and profitability estimates. We will continue to focus on our role of replicating the structure and performance of the S&P indexes to provide you with broad exposure to large-cap stocks, small- and mid-cap equities, and the entire U.S. stock market.

Respectfully submitted,

E. Frederick Bair
Cochairman of the Investment Advisory Committee, Equity Index 500 Fund, Total Equity Market Index Fund, and Extended Equity Market Index Fund

Ken D. Uematsu
Cochairman of the Investment Advisory Committee, Equity Index 500 Fund, Total Equity Market Index Fund, and Extended Equity Market Index Fund

July 22, 2011

The committee chairmen have day-to-day responsibility for managing the portfolios and work with committee members in developing and executing the funds’ investment programs.

RISKS OF INVESTING

As with all stock mutual funds, the fund’s share price can fall because of weakness in the stock market, a particular industry, or specific holdings. Stock markets can decline for many reasons, including adverse political or economic developments, changes in investor psychology, or heavy institutional selling. The prospects for an industry or company may deteriorate because of a variety of factors, including disappointing earnings or changes in the competitive environment.

GLOSSARY

Dow Jones Wilshire 4500 Completion Index: An unmanaged index that tracks the performance of all stocks in the Dow Jones Wilshire 5000 Completion Index, excluding those found in the S&P 500 Index.

Dow Jones Wilshire 5000 Composite Index: An unmanaged index that tracks the performance of the most active stocks in the broad U.S. market.

Price-to-earnings (P/E) ratio: A valuation measure calculated by dividing the price of a stock by its reported earnings per share. The ratio is a measure of how much investors are willing to pay for the company’s earnings.

S&P 500 Index: Tracks the stocks of 500 mostly large U.S. companies.

S&P Completion Index: Tracks the performance of the U.S. stocks not included in the S&P 500, which are primarily small- and mid-capitalization stocks. The index includes approximately 4,000 stocks.

S&P Total Market Index: Tracks the performance of a broad spectrum of small-, mid-, and large-capitalization U.S. stocks. Because the largest stocks in the index carry the most weight, large-capitalization stocks make up a substantial majority of the S&P Total Market Index’s value. The index includes approximately 4,500 stocks.

Performance and Expenses

GROWTH OF $10,000 

This chart shows the value of a hypothetical $10,000 investment in the fund over the past 10 fiscal year periods or since inception (for funds lacking 10-year records). The result is compared with benchmarks, which may include a broad-based market index and a peer group average or index. Market indexes do not include expenses, which are deducted from fund returns as well as mutual fund averages and indexes.

GROWTH OF $10,000 

This chart shows the value of a hypothetical $10,000 investment in the fund over the past 10 fiscal year periods or since inception (for funds lacking 10-year records). The result is compared with benchmarks, which may include a broad-based market index and a peer group average or index. Market indexes do not include expenses, which are deducted from fund returns as well as mutual fund averages and indexes.

GROWTH OF $10,000 

This chart shows the value of a hypothetical $10,000 investment in the fund over the past 10 fiscal year periods or since inception (for funds lacking 10-year records). The result is compared with benchmarks, which may include a broad-based market index and a peer group average or index. Market indexes do not include expenses, which are deducted from fund returns as well as mutual fund averages and indexes.

FUND EXPENSE EXAMPLE 

As a mutual fund shareholder, you may incur two types of costs: (1) transaction costs, such as redemption fees or sales loads, and (2) ongoing costs, including management fees, distribution and service (12b-1) fees, and other fund expenses. The following example is intended to help you understand your ongoing costs (in dollars) of investing in the fund and to compare these costs with the ongoing costs of investing in other mutual funds. The example is based on an investment of $1,000 invested at the beginning of the most recent six-month period and held for the entire period.

Actual Expenses
The first line of the following table (“Actual”) provides information about actual account values and actual expenses. You may use the information on this line, together with your account balance, to estimate the expenses that you paid over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number on the first line under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

Hypothetical Example for Comparison Purposes
The information on the second line of the table (“Hypothetical”) is based on hypothetical account values and expenses derived from the fund’s actual expense ratio and an assumed 5% per year rate of return before expenses (not the fund’s actual return). You may compare the ongoing costs of investing in the fund with other funds by contrasting this 5% hypothetical example and the 5% hypothetical examples that appear in the shareholder reports of the other funds. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period.

Note: T. Rowe Price charges an account service fee that is not included in the accompanying table. The account service fee is charged on a quarterly basis, usually during the last week of a calendar quarter, and applies to accounts with balances below $10,000 on the day of the assessment. The fee is charged to accounts that fall below $10,000 for any reason, including market fluctuations, redemptions, or exchanges. When an account with less than $10,000 is closed either through redemption or exchange, the fee is charged and deducted from the proceeds. The fee applies to IRAs but not to retirement plans directly registered with T. Rowe Price Services or accounts maintained by intermediaries through NSCC^® Networking. If you are subject to the fee, keep it in mind when you are estimating the ongoing expenses of investing in the fund and when comparing the expenses of this fund with other funds.

You should also be aware that the expenses shown in the table highlight only your ongoing costs and do not reflect any transaction costs, such as redemption fees or sales loads. Therefore, the second line of the table is useful in comparing ongoing costs only and will not help you determine the relative total costs of owning different funds. To the extent a fund charges transaction costs, however, the total cost of owning that fund is higher.

Unaudited

The accompanying notes are an integral part of these financial statements.

Unaudited

The accompanying notes are an integral part of these financial statements.

Unaudited

The accompanying notes are an integral part of these financial statements.

Unaudited

The accompanying notes are an integral part of these financial statements.

Unaudited

The accompanying notes are an integral part of these financial statements.

Unaudited

NOTES TO FINANCIAL STATEMENTS 

T. Rowe Price Index Trust, Inc. (the trust), is registered under the Investment Company Act of 1940 (the 1940 Act). The Extended Equity Market Index Fund (the fund), a diversified, open-end management investment company, is one portfolio established by the trust. The fund commenced operations on January 30, 1998. The fund seeks to match the performance of the U.S. stocks not included in the Standard & Poor’s 500 Stock Index^®, as represented by the S&P Completion Index.

NOTE1-SIGNIFICANTACCOUNTING POLICIES

Basisof Preparation The accompanying financial statements were prepared in accordance with accounting principles generally accepted in the United States of America (GAAP), which require the use of estimates made by management. Management believes that estimates and valuations are appropriate; however, actual results may differ from those estimates, and the valuations reflected in the accompanying financial statements may differ from the value ultimately realized upon sale or maturity.

InvestmentTransactions,InvestmentIncome,andDistributions Income and expenses are recorded on the accrual basis. Premiums and discounts on debt securities are amortized for financial reporting purposes. Dividends received from mutual fund investments are reflected as dividend income; capital gain distributions are reflected as realized gain/loss. Dividend income and capital gain distributions are recorded on the ex-dividend date. Income tax-related interest and penalties, if incurred, would be recorded as income tax expense. Investment transactions are accounted for on the trade date. Realized gains and losses are reported on the identified cost basis. Distributions to shareholders are recorded on the ex-dividend date. Income distributions are declared and paid annually. Capital gain distributions, if any, are generally declared and paid by the fund annually.

Rebates Subject to best execution, the fund may direct certain security trades to brokers who have agreed to rebate a portion of the related brokerage commission to the fund in cash. Commission rebates are reflected as realized gain on securities in the accompanying financial statements.

Credits Credits are earned on the fund’s temporarily uninvested cash balances held at the custodian and such credits reduce the amount paid by the manager for custody of the fund’s assets. In order to pass the benefit of custody credits to the fund, the manager has voluntarily reduced its investment management and administrative expense in the accompanying financial statements.

RedemptionFees A 0.5% fee is assessed on redemptions of fund shares held for 90 days or less to deter short-term trading and to protect the interests of long-term shareholders. Redemption fees are withheld from proceeds that shareholders receive from the sale or exchange of fund shares. The fees are paid to the fund and are recorded as an increase to paid-in capital. The fees may cause the redemption price per share to differ from the net asset value per share.

NOTE2-VALUATION

The fund’s financial instruments are reported at fair value as defined by GAAP. The fund determines the values of its assets and liabilities and computes its net asset value per share at the close of the New York Stock Exchange (NYSE), normally 4 p.m. ET, each day that the NYSE is open for business.

Valuation Methods Equity securities listed or regularly traded on a securities exchange or in the over-the-counter (OTC) market are valued at the last quoted sale price at the time the valuations are made, except for OTC Bulletin Board securities, which are valued at the mean of the latest bid and asked prices. A security that is listed or traded on more than one exchange is valued at the quotation on the exchange determined to be the primary market for such security. Listed securities not traded on a particular day are valued at the mean of the latest bid and asked prices. Debt securities with remaining maturities of less than one year at the time of acquisition generally use amortized cost in local currency to approximate fair value. However, if amortized cost is deemed not to reflect fair value or the fund holds a significant amount of such securities with remaining maturities of more than 60 days, the securities are valued at prices furnished by dealers who make markets in such securities or by an independent pricing service.

Investments in mutual funds are valued at the mutual fund’s closing net asset value per share on the day of valuation. Financial futures contracts are valued at closing settlement prices.

Other investments, including restricted securities, and those financial instruments for which the above valuation procedures are inappropriate or are deemed not to reflect fair value are stated at fair value as determined in good faith by the T. Rowe Price Valuation Committee, established by the fund’s Board of Directors.

ValuationInputs Various inputs are used to determine the value of the fund’s financial instruments. These inputs are summarized in the three broad levels listed below:

Level 1 – quoted prices in active markets for identical financial instruments

Level 2 – observable inputs other than Level 1 quoted prices (including, but not limited to, quoted prices for similar financial instruments, interest rates, prepayment speeds, and credit risk)

Level 3 – unobservable inputs

Observable inputs are those based on market data obtained from sources independent of the fund, and unobservable inputs reflect the fund’s own assumptions based on the best information available. The input levels are not necessarily an indication of the risk or liquidity associated with financial instruments at that level. The following table summarizes the fund’s financial instruments, based on the inputs used to determine their values on June 30, 2011:

Following is a reconciliation of the fund’s Level 3 holdings for the six months ended June 30, 2011. Gain (loss) reflects both realized and change in unrealized gain (loss) on Level 3 holdings during the period, if any, and is included on the accompanying Statement of Operations. The change in unrealized gain (loss) on Level 3 instruments held at June 30, 2011, totaled $2,000 for the six months ended June 30, 2011.

NOTE3-DERIVATIVEINSTRUMENTS

During the six months ended June 30, 2011, the fund invested in derivative instruments. As defined by GAAP, a derivative is a financial instrument whose value is derived from an underlying security price, foreign exchange rate, interest rate, index of prices or rates, or other variable; it requires little or no initial investment and permits or requires net settlement. The fund invests in derivatives only if the expected risks and rewards are consistent with its investment objectives, policies, and overall risk profile, as described in its prospectus and Statement of Additional Information. The fund may use derivatives for a variety of purposes, such as seeking to hedge against declines in principal value, increase yield, invest in an asset with greater efficiency and at a lower cost than is possible through direct investment, or to adjust credit exposure. The risks associated with the use of derivatives are different from, and potentially much greater than, the risks associated with investing directly in the instruments on which the derivatives are based. Investments in derivatives can magnify returns positively or negatively; however, the fund at all times maintains sufficient cash reserves, liquid assets, or other SEC-permitted asset types to cover the settlement obligations under its open derivative contracts.

The fund values its derivatives at fair value, as described below and in Note 2, and recognizes changes in fair value currently in its results of operations. Accordingly, the fund does not follow hedge accounting, even for derivatives employed as economic hedges. The fund does not offset the fair value of derivative instruments against the right to reclaim or obligation to return collateral. As of June 30, 2011, the fund held equity futures with cumulative unrealized gain of $872,000 and cumulative unrealized loss of $0; the value reflected on the accompanying Statement of Assets and Liabilities is the related unsettled variation margin.

Additionally, during the six months ended June 30, 2011, the fund recognized $165,000 of realized loss on Futures and a $697,000 change in unrealized gain on Futures related to its investments in equity derivatives; such amounts are included on the accompanying Statement of Operations.

Counterparty risk related to exchange-traded derivatives, including futures and options contracts, is minimal because the exchange’s clearinghouse provides protection against defaults. Additionally, for exchange-traded derivatives, each broker, in its sole discretion, may change margin requirements applicable to the fund.

FuturesContracts The fund is subject to equity price risk in the normal course of pursuing its investment objectives and uses futures contracts to help manage such risk. The fund may enter into futures contracts as an efficient means of maintaining liquidity while being invested in the market, to facilitate trading, and/or to reduce transaction costs. A futures contract provides for the future sale by one party and purchase by another of a specified amount of a particular underlying financial instrument at an agreed-upon price, date, time, and place. The fund currently invests only in exchange-traded futures, which generally are standardized as to maturity date, underlying financial instrument, and other contract terms. Upon entering into a futures contract, the fund is required to deposit with the broker cash or securities in an amount equal to a certain percentage of the contract value (initial margin deposit); the margin deposit must then be maintained at the established level over the life of the contract. Subsequent payments are made or received by the fund each day to settle daily fluctuations in the value of the contract (variation margin), which reflect changes in the value of the underlying financial instrument. Variation margin is recorded as unrealized gain or loss until the contract is closed. The value of a futures contract included in net assets is the amount of unsettled variation margin; net variation margin receivable is reflected as an asset, and net variation margin payable is reflected as a liability on the accompanying Statement of Assets and Liabilities. Risks related to the use of futures contracts include possible illiquidity of the futures markets, contract prices that can be highly volatile and imperfectly correlated to movements in hedged security values and potential losses in excess of the fund’s initial investment. During the six months ended June 30, 2011, the fund’s exposure to futures, based on underlying notional amounts, was generally less than 1% of net assets.

NOTE4-OTHERINVESTMENTTRANSACTIONS

Consistent with its investment objective, the fund engages in the following practices to manage exposure to certain risks and/or to enhance performance. The investment objective, policies, program, and risk factors of the fund are described more fully in the fund’s prospectus and Statement of Additional Information.

SecuritiesLending The fund lends its securities to approved brokers to earn additional income. It receives as collateral cash and U.S. government securities valued at 102% to 105% of the value of the securities on loan. Cash collateral is invested by the fund’s lending agent(s) in accordance with investment guidelines approved by management. Although risk is mitigated by the collateral, the fund could experience a delay in recovering its securities and a possible loss of income or value if the borrower fails to return the securities or if collateral investments decline in value. Securities lending revenue recognized by the fund consists of earnings on invested collateral and borrowing fees, net of any rebates to the borrower and compensation to the lending agent. In accordance with GAAP, investments made with cash collateral are reflected in the accompanying financial statements, but collateral received in the form of securities are not. On June 30, 2011, the value of loaned securities was $67,398,000 and cash collateral investments totaled $68,727,000.

Other Purchases and sales of portfolio securities other than short-term securities aggregated $45,601,000 and $35,931,000, respectively, for the six months ended June 30, 2011.

NOTE5-FEDERALINCOMETAXES

No provision for federal income taxes is required since the fund intends to continue to qualify as a regulated investment company under Subchapter M of the Internal Revenue Code and distribute to shareholders all of its taxable income and gains. Distributions determined in accordance with federal income tax regulations may differ in amount or character from net investment income and realized gains for financial reporting purposes. Financial reporting records are adjusted for permanent book/tax differences to reflect tax character but are not adjusted for temporary differences. The amount and character of tax-basis distributions and composition of net assets are finalized at fiscal year-end; accordingly, tax-basis balances have not been determined as of the date of this report.

The fund intends to retain realized gains to the extent of available capital loss carryforwards. As of December 31, 2010, the fund had $17,226,000 of unused capital loss carryforwards, which expire: $776,000 in fiscal 2016 and $16,450,000 in fiscal 2017.

At June 30, 2011, the cost of investments for federal income tax purposes was $370,858,000. Net unrealized gain aggregated $103,261,000 at period-end, of which $131,654,000 related to appreciated investments and $28,393,000 related to depreciated investments.

NOTE6-RELATED PARTYTRANSACTIONS

The fund is managed by T. Rowe Price Associates, Inc. (Price Associates), a wholly owned subsidiary of T. Rowe Price Group, Inc. (Price Group). The investment management and administrative agreement between the fund and Price Associates provides for an all-inclusive annual fee equal to 0.40% of the fund’s average daily net assets. The fee is computed daily and paid monthly. The all-inclusive fee covers investment management, shareholder servicing, transfer agency, accounting, and custody services provided to the fund, as well as fund directors’ fees and expenses; interest, taxes, brokerage commissions, and extraordinary expenses are paid directly by the fund.

Additionally, the fund is one of several mutual funds in which certain college savings plans managed by Price Associates may invest. As approved by the fund’s Board of Directors, shareholder servicing costs associated with each college savings plan are allocated to the fund in proportion to the average daily value of its shares owned by the college savings plan. Shareholder servicing costs allocated to the fund are borne by Price Associates, pursuant to the fund’s all-inclusive fee agreement. At June 30, 2011, approximately 1% of the outstanding shares of the fund were held by college savings plans.

The fund may invest in the T. Rowe Price Reserve Investment Fund and the T. Rowe Price Government Reserve Investment Fund (collectively, the T. Rowe Price Reserve Investment Funds), open-end management investment companies managed by Price Associates and considered affiliates of the fund. The T. Rowe Price Reserve Investment Funds are offered as cash management options to mutual funds, trusts, and other accounts managed by Price Associates and/or its affiliates and are not available for direct purchase by members of the public. The T. Rowe Price Reserve Investment Funds pay no investment management fees.

INFORMATION ON PROXY VOTING POLICIES, PROCEDURES, AND RECORDS 

A description of the policies and procedures used by T. Rowe Price funds and portfolios to determine how to vote proxies relating to portfolio securities is available in each fund’s Statement of Additional Information, which you may request by calling 1-800-225-5132 or by accessing the SEC’s website, sec.gov. The description of our proxy voting policies and procedures is also available on our website, troweprice.com. To access it, click on the words “Our Company” at the top of our corporate homepage. Then, when the next page appears, click on the words “Proxy Voting Policies” on the left side of the page.

Each fund’s most recent annual proxy voting record is available on our website and through the SEC’s website. To access it through our website, follow the directions above, then click on the words “Proxy Voting Records” on the right side of the Proxy Voting Policies page.

HOW TO OBTAIN QUARTERLY PORTFOLIO HOLDINGS 

The fund files a complete schedule of portfolio holdings with the Securities and Exchange Commission for the first and third quarters of each fiscal year on Form N-Q. The fund’s Form N-Q is available electronically on the SEC’s website (sec.gov); hard copies may be reviewed and copied at the SEC’s Public Reference Room, 450 Fifth St. N.W., Washington, DC 20549. For more information on the Public Reference Room, call 1-800-SEC-0330.

APPROVAL OF INVESTMENT MANAGEMENT AGREEMENT  

On March 9, 2011, the fund’s Board of Directors (Board) unanimously approved the continuation of the investment advisory contract (Contract) between the fund and its investment advisor, T. Rowe Price Associates, Inc. (Advisor). The Board considered a variety of factors in connection with its review of the Contract, also taking into account information provided by the Advisor during the course of the year, as discussed below:

Services ProvidedbytheAdvisor
The Board considered the nature, quality, and extent of the services provided to the fund by the Advisor. These services included, but were not limited to, management of the fund’s portfolio and a variety of related activities, as well as financial and administrative services, reporting, and communications. The Board also reviewed the background and experience of the Advisor’s senior management team and investment personnel involved in the management of the fund. The Board concluded that it was satisfied with the nature, quality, and extent of the services provided by the Advisor.

Investment PerformanceoftheFund
The Board reviewed the fund’s average annual total returns over the 1-, 3-, 5-, and 10-year periods, as well as the fund’s year-by-year returns, and compared these returns with a wide variety of previously agreed upon comparable performance measures and market data, including those supplied by Lipper and Morningstar, which are independent providers of mutual fund data. On the basis of this evaluation and the Board’s ongoing review of investment results, and factoring in the relative market conditions during certain of the performance periods, the Board concluded that the fund’s performance was satisfactory.

Costs,Benefits, Profits,andEconomiesofScale
The Board reviewed detailed information regarding the revenues received by the Advisor under the Contract and other benefits that the Advisor (and its affiliates) may have realized from its relationship with the fund, including research received under “soft dollar” agreements and commission-sharing arrangements with broker-dealers. The Board considered that the Advisor may receive some benefit from soft-dollar arrangements pursuant to which research is received from broker-dealers that execute the applicable fund’s portfolio transactions. The Board also received information on the estimated costs incurred and profits realized by the Advisor and its affiliates from advising T. Rowe Price mutual funds. The Board did not review information regarding profits realized from managing the fund in particular because the fund had not achieved sufficient scale in terms of portfolio asset size to produce meaningful profit margin percentages. The Board concluded that the Advisor’s profits were reasonable in light of the services provided to the fund. The Board also considered whether the fund or other funds benefit under the fee levels set forth in the Contract from any economies of scale realized by the Advisor. The Board noted that, under the Contract, the fund pays the Advisor a single fee based on the fund’s average daily net assets and that the Advisor, in turn, pays all expenses of the fund, with certain exceptions. The Board concluded that, based on the profitability data it reviewed and consistent with this single-fee structure, the Contract provided for a reasonable sharing of any benefits from economies of scale with the fund.

Fees
The Board reviewed the fund’s single-fee structure and compared it with fees and expenses of other comparable funds based on information and data supplied by Lipper. The information provided to the Board indicated that the fund’s management fee rate was below the median for comparable funds. (For these purposes, the Board assumed the fund’s management fee rate was equal to the single fee less the fund’s operating expenses.) The information also indicated that the fund’s total expense ratio was above the median for certain groups of comparable funds but below the median for other groups of comparable funds. The Board also reviewed the fee schedules for institutional accounts of the Advisor and its affiliates with similar mandates. Management provided the Board with information about the Advisor’s responsibilities and services provided to institutional account clients, which are more limited than its responsibilities for the fund and other T. Rowe Price mutual funds that it advises, and showing that the Advisor performs significant additional services and assumes greater risk for the fund and other T. Rowe Price mutual funds that it advises than it does for institutional account clients. On the basis of the information provided, the Board concluded that the fees paid by the fund under the Contract were reasonable.

ApprovaloftheContract
As noted, the Board approved the continuation of the Contract. No single factor was considered in isolation or to be determinative to the decision. Rather, the Board was assisted by the advice of independent legal counsel and concluded, in light of a weighting and balancing of all factors considered, that it was in the best interests of the fund to approve the continuation of the Contract (including the fees to be charged for services thereunder).

Item 2. Code of Ethics.

A code of ethics, as defined in Item 2 of Form N-CSR, applicable to its principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions is filed as an exhibit to the registrant’s annual Form N-CSR. No substantive amendments were approved or waivers were granted to this code of ethics during the registrant’s most recent fiscal half-year.

Item 3. Audit Committee Financial Expert.

Disclosure required in registrant’s annual Form N-CSR.

Item 4. Principal Accountant Fees and Services.

Disclosure required in registrant’s annual Form N-CSR.

Item 5. Audit Committee of Listed Registrants.

Not applicable.

Item 6. Investments.

(a) Not applicable. The complete schedule of investments is included in Item 1 of this Form N-CSR.

(b) Not applicable.

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies.

Not applicable.

Item 8. Portfolio Managers of Closed-End Management Investment Companies.

Not applicable.

Item 9. Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers.

Not applicable.

Item 10. Submission of Matters to a Vote of Security Holders.

Not applicable.

Item 11. Controls and Procedures.

(a) The registrant’s principal executive officer and principal financial officer have evaluated the registrant’s disclosure controls and procedures within 90 days of this filing and have concluded that the registrant’s disclosure controls and procedures were effective, as of that date, in ensuring that information required to be disclosed by the registrant in this Form N-CSR was recorded, processed, summarized, and reported timely.

(b) The registrant’s principal executive officer and principal financial officer are aware of no change in the registrant’s internal control over financial reporting that occurred during the registrant’s second fiscal quarter covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 12. Exhibits.

(a)(1) The registrant’s code of ethics pursuant to Item 2 of Form N-CSR is filed with the registrant’s annual Form N-CSR.

    (2) Separate certifications by the registrant's principal executive officer and principal financial officer, pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 and required by Rule 30a-2(a) under the Investment Company Act of 1940, are attached.

    (3) Written solicitation to repurchase securities issued by closed-end companies: not applicable.

(b) A certification by the registrant's principal executive officer and principal financial officer, pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 and required by Rule 30a-2(b) under the Investment Company Act of 1940, is attached.

SIGNATURES
	Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment
Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.
T. Rowe Price Index Trust, Inc.
By	/s/ Edward C. Bernard
	Edward C. Bernard
	Principal Executive Officer
Date	August 17, 2011
	Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment
Company Act of 1940, this report has been signed below by the following persons on behalf of
the registrant and in the capacities and on the dates indicated.
By	/s/ Edward C. Bernard
	Edward C. Bernard
	Principal Executive Officer
Date	August 17, 2011
By	/s/ Gregory K. Hinkle
	Gregory K. Hinkle
	Principal Financial Officer
Date	August 17, 2011