N-CSRS

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: 811-958 

T. Rowe Price New Horizons Fund, 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, 2010 

Item 1: Report to Shareholders

 New Horizons Fund June 30, 2010 

The views and opinions in this report were current as of June 30, 2010. 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.

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Manager’s Letter

Fellow Shareholders

Investors went on a roller coaster ride for the last six months. The stock market faltered at the beginning of the year but gained momentum in February and March. By the end of the first quarter, it was climbing steadily. The upward push was cut short in early May when the market experienced a “flash crash” and the Dow Jones Industrial Average plummeted about 1,000 points in one afternoon. Concerns about the Greek debt crisis, stability of the euro, and strength of the U.S. economic recovery added to investor unease and pushed stocks lower for the remainder of the quarter. As the six-month period came to a close, the optimistic outlooks of the beginning of the year were replaced by grimmer forecasts, and major market indices closed below where they started the year. Your fund’s return was essentially flat.

PERFORMANCE COMPARISON

As shown in the accompanying Performance Comparison table, the New Horizons Fund returned -0.27% for the six months ended June 30, 2010, outpacing the small-cap Russell 2000 Index and the more relevant Russell 2000 Growth Index. A decline in the stock market in May and June wiped out the gains of the earlier months. Overall, during the last six months, small-caps held up significantly better than large-caps, but small-cap growth stocks—the focus of your fund’s investment program—lost slightly more ground than small-cap value stocks.

During the last six months, the New Horizons Fund outpaced its peer group of similarly managed funds—the Lipper Small-Cap Growth Funds Index. The fund’s long-term relative performance also continued to be strong. Lipper ranked the New Horizons Fund 70 out of 534, 67 out of 469, 107 out of 394, and 34 out of 218 small-cap growth funds for the 1-, 3-, 5-, and 10-year periods ended June 30, 2010, respectively. (Results will vary for other time periods. Past performance cannot guarantee future results.)

On June 3, 2010, the New Horizons Fund marked its 50th anniversary. In 1960, Thomas Rowe Price, Jr., who successfully applied his growth stock investment approach to large-cap stocks, created a mutual fund that would invest in entrepreneurial, “emerging growth” companies with the potential to grow rapidly into larger enterprises. Mr. Price’s vision was bold. Most investors at the time considered investing in these small-cap companies with their uncertain futures much too risky. Mr. Price believed that these innovative and flexible companies had considerable leverage and could, with proper management, double and triple in size.

Five decades later, we can appreciate the wisdom of Mr. Price’s vision. Some of his early successful investments were in Xerox, Texas Instruments, H&R Block, and Eckerd Drugs, which the fund no longer owns. His successors continued the tradition by investing in the next generation of dynamic small companies—including Wal-Mart, Starbucks, Paychex, and Medco Health—that became today’s industry giants. The fund sold these off as they grew, but still owns Paychex. As a result, the fund has generated solid long-term results, with an annualized return of 10.43% for the period since the fund’s inception on June 3, 1960, to June 30, 2010. (For the 1-year, 5-year, and 10-year periods ended June 30, 2010, the fund’s average annualized returns were 24.21%, 1.67%, and 2.26%, respectively. Current performance may be higher or lower than the quoted past performance, which cannot guarantee future results. Share price, principal value, and return will vary, and you may have a gain or loss when you sell your shares. To obtain the most recent month-end performance, please call 1-800-225-5132. The fund’s expense ratio was 0.85% as of its fiscal year ended December 31, 2009. Please refer to the portfolio of investments for a complete listing of fund holdings and the amount each represents in the portfolio.)

I am proud to be the fund’s seventh portfolio manager. I want to recognize my predecessor Jack Laporte for his success over the past 23 years and his mentorship of a new generation of investors. Supported by a strong team of analysts, I remain focused on the same core mission of identifying and investing in the leading companies of tomorrow.

How will we achieve this? We will invest in three major groups of companies—potential long-term winners, durable niche growth companies, and out-of-favor durable brand companies. Our potential long-term winners are companies with innovative, high-potential business models that operate in large, changing markets; create value for customers; and have the financial models to support their rapid growth. We look for management teams and a corporate culture that can learn and adapt. The durable niche growth companies possess a strong franchise with good prospects for growth, are led by solid management, and generate a high return on their invested capital. The last group that we will focus on are the out-of-favor durable brand companies that have a strong franchise and generate high returns but temporarily may be experiencing slower growth.

We remain committed to having a diversified portfolio because opportunity exists throughout the economy. We are focusing additional resources on seven areas of innovation—media and technology convergence, alternative energy, health care information technology, genomics, value-added distribution, financial payments technology, and collaborative and aggregate data businesses. As a whole, these areas currently make up about a quarter of the portfolio’s assets. Some of the areas, like value-added distribution, have yielded leading holdings such as Henry Schein. Others, such as alternative energy, have limited current investment, but we believe they will provide opportunity for the patient and prepared investor.

MARKET ENVIRONMENT

The bull market that began in March 2009 came to an end in late April 2010 as investors reacted to revelations about a growing sovereign debt crisis in Greece. The failure to resolve Greece’s problems quickly threatened to provoke a broader credit crisis in Europe and drag the world back into recession. A mysterious “flash crash” in U.S. stock prices on May 6, 2010, also unsettled markets. The explosion of the Deepwater Horizon drilling rig in the Gulf of Mexico and subsequent uncontrolled outflow of crude oil created one of the largest environmental disasters in U.S. history and further soured investor sentiment.

Although conclusive data on U.S. economic growth in the second quarter are not yet available, it appears that the springtime turmoil led to some heightened caution on the part of employers and consumers. After expanding sharply in April, private payroll growth, retail spending, and consumer confidence all decelerated or declined in May and June. The housing market appeared to lose momentum as well. New home sales jumped in March by their highest percentage since 1963 as buyers rushed to take advantage of expiring tax incentives. By May, sales of both existing and new homes were falling, which raised fears about how the sector would fare without homebuyer tax credits. The manufacturing sector, boosted by inventory restocking and exports, remained the bright spot in the recovery.

Corporate profits expanded at a healthy clip early in the year. Cost-cutting, rising worker productivity, and healthy exports should help corporate bottom lines for the remainder of the year. Nevertheless, the stock market sold off sharply in May and June. Despite the pull-back, most major indexes remained more than 50% above their March 2009 nadir.

PORTFOLIO REVIEW

Most of our holdings declined over the most recent six-month period, but our stock and sector performance varied. Our small holding of consumer staples was the only sector that gained. Our worst-performing sectors were consumer discretionary and health care.

Ironically, two of our best-performing stocks—O’Reilly Automotive and Chipotle Mexican Grill—for the period came from our weakest-performing sector, consumer discretionary. O’Reilly Automotive, an auto parts retailer and one of the fund’s top holdings, has been a long-time portfolio holding. It has the characteristics of both a long-term winner and a durable niche company. Focused on the auto parts business for do-it-yourself consumers and professional auto repair shops, it has a large and lucrative potential market. By focusing on selection, price, and personal service, it is largely insulated from general purpose retailers such as Wal-Mart and Amazon.com. The company has been able to grow geographically by organic and acquired investments. Most recently, management has demonstrated considerable progress integrating the operations of CSK Auto Stores. Despite a weak environment for restaurants generally, Chipotle Mexican Grill managed to show strong results thanks to its consumer value proposition and strong brand. It benefits from the growing popularity of fast casual eateries that are slightly upscale from fast-food restaurants but offer affordable meals. Chipotle’s efficient operation generates high returns, which allows it to fund its new units.

On the flip side, investors punished billboard company Lamar Advertising for its slow recovery. Although market conditions for media companies are improving, the improvement in the local advertising market has taken longer. We continue to like Lamar for the following reasons: Lamar has a strong core business, it is a leader in digital billboards that expand market opportunity, and it has a cost-efficient and focused management team. Electronic commerce processor Global Payments also stumbled. The company suffered from slower-than-expected growth in its mature markets in the U.S. and Canada and exhibited solid growth and expanding market share overseas. We still like this company, but, as with all our investments, we remain vigilant.

We added several new names to our portfolio. Solera Holdings is a leading global provider of automobile claims processing software and services. The company, with an unmatched set of global databases, products, and services and a network of relationships, processes about $20 billion in claims annually for 72,000 customers in more than 50 countries across the globe. Solera is a capital-efficient company that has an attractive and scalable operating model. Our focus on the collaborative data field generated this investment. We also initiated a position in Rackspace Hosting, a provider of managed hosting computer services. Rackspace is leveraging its technological skill and service expertise to become a significant player in the emerging field of cloud computing—delivering technology capabilities over the Internet. Cloud computing is an area of rapid innovation that is garnering considerable interest from corporate technology departments, and we believe it will be an increasingly important driver of future technology spending.

In an improving year for merger and acquisition activity, a number of our holdings were bought out, including OSI Pharmaceuticals, Riskmetrics Group, Arena Resources, and Skilsoft. We sold off all of our holdings in oil and production company Bill Barrett and renal dialysis provider DaVita and trimmed positions in mobile phone company NII Holdings and FMC Technologies, a supplier of components used in subsea oil production and processing.

OUTLOOK

Despite the weak performance of the first half of this year, I remain cautiously optimistic that the market will move ahead. On the positive side, the U.S. economy is continuing to expand and emerging market growth is creating new markets for our global goods and services. The Federal Reserve’s monetary policy remains accommodative and eventually should stimulate borrowing and new investment. And corporate balance sheets remain strong. On the other side of the ledger, the consumer continues to deleverage from its consumption hangover; government deficits in the U. S., Europe, and Japan need to be reduced; and the income and opportunity gap between segments of the U.S. population continue to widen.

Small-cap stocks, which have led the market recovery from the March 2009 lows, should participate in any further market advance. Additional strength in small-cap stock prices relative to large-caps depends on a sharper earnings recovery for small-cap companies, which we expect. Based on near-term price/earnings (P/E) valuations, small-caps appear expensive, selling at a historically high premium compared with large-caps. The New Horizons Fund relative P/E compared with the S&P 500 on expected 12-month forward earnings is 1.9, its highest level since 1983. However, on an absolute basis, the small-cap P/E remains near its median. On other valuation metrics, including price/book and price/cash flow, small-caps are in line with historical levels.

Despite some turbulent macroeconomic conditions in the U.S. and other developed markets, we believe that there are opportunities in the market. We remain focused on our goals of achieving long-term capital growth by investing in the leading companies of tomorrow. T. Rowe Price’s team of research analysts continues to find many exciting small-cap companies with strong earnings potential. Even in this relatively weak economic environment, we believe our diversified portfolio of high-growth, small-cap companies can deliver earnings growth and deliver attractive absolute returns to shareholders over time.

Respectfully submitted,

Henry Ellenbogen
President of the fund and chairman of its Investment Advisory Committee

July 19, 2010

The committee chairman has day-to-day responsibility for managing the portfolio and works with committee members in developing and executing the fund’s investment program.

RISKS OF STOCK INVESTING

As with all stock and bond mutual funds, each fund’s share price can fall because of weakness in the stock or bond markets, 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. In addition, the investment manager’s assessment of companies held in a fund may prove incorrect, resulting in losses or poor performance even in rising markets.

Investing in small companies involves greater risk than is customarily associated with larger companies. Stocks of small companies are subject to more abrupt or erratic price movements than larger-company stocks. Small companies often have limited product lines, markets, or financial resources, and their managements may lack depth and experience. Such companies seldom pay significant dividends that could cushion returns in a falling market.

GLOSSARY

Lipper indexes: Fund benchmarks that consist of a small number (10 to 30) of the largest mutual funds in a particular category as tracked by Lipper Inc.

Price/earnings (P/E) ratio: A valuation measure calculated by dividing the price of a stock by its current or projected earnings per share. This ratio gives investors an idea of how much they are paying for current or future earnings power.

Russell 2000 Index: Consists of the smallest 2,000 companies in the Russell 3000 Index, representing approximately 8% of the Russell 3000’s total market capitalization. Performance is reported on a total return basis.

Russell 2000 Growth Index: A market-weighted total return index that measures the performance of companies within the Russell 2000 Index having higher price/book value ratios and higher forecasted growth rates.

Russell 2000 Value Index: A market-weighted total return index that measures the performance of companies within the Russell 2000 Index having lower price/book value ratios and lower forecasted growth rates.

Russell 3000 Index: An index that measures the performance of 3,000 publicly held U.S. companies whose total market capitalization represents about 98% of the investable U.S. market.

S&P 500 Index: An unmanaged index that tracks the stocks of 500 primarily large-cap U.S. companies.

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.

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 expenses based on the fund’s actual returns. You may use the information in 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 in 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 annual small-account maintenance fee of $10, generally for accounts with less than $2,000 ($500 for UGMA/UTMA). The fee is waived for any investor whose T. Rowe Price mutual fund accounts total $25,000 or more, accounts employing automatic investing, and IRAs and other retirement plan accounts that utilize a prototype plan sponsored by T. Rowe Price (although a separate custodial or administrative fee may apply to such accounts). This fee is not included in the accompanying table. 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 New Horizons Fund (the fund), is registered under the Investment Company Act of 1940 (the 1940 Act) as a diversified, open-end management investment company. The fund commenced operations on June 3, 1960. The fund seeks long-term capital growth by investing primarily in common stocks of small, rapidly growing companies.

NOTE 1 - SIGNIFICANT ACCOUNTING POLICIES

Basis of 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 fund management. Fund 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 of securities.

Investment Transactions, Investment Income, and Distributions 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.

Currency Translation Assets, including investments, and liabilities denominated in foreign currencies are translated into U.S. dollar values each day at the prevailing exchange rate, using the mean of the bid and asked prices of such currencies against U.S. dollars as quoted by a major bank. Purchases and sales of securities, income, and expenses are translated into U.S. dollars at the prevailing exchange rate on the date of the transaction. The effect of changes in foreign currency exchange rates on realized and unrealized security gains and losses is reflected as a component of security gains and losses.

Rebates and Credits 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 and totaled $127,000 for the six months ended June 30, 2010. Additionally, the fund earns credits on temporarily uninvested cash balances held at the custodian, which reduce the fund’s custody charges. Custody expense in the accompanying financial statements is presented before reduction for credits.

New Accounting Pronouncement On January 1, 2010, the fund adopted new accounting guidance that requires enhanced disclosures about fair value measurements in the financial statements. Adoption of this guidance had no impact on the fund’s net assets or results of operations.

NOTE 2 - VALUATION

The fund’s investments 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 or, for certain markets, the official closing 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 for domestic securities and the last quoted sale price for international securities.

Debt securities are generally traded in the OTC market. Securities with remaining maturities of one year or more at the time of acquisition are valued at prices furnished by dealers who make markets in such securities or by an independent pricing service, which considers the yield or price of bonds of comparable quality, coupon, maturity, and type, as well as prices quoted by dealers who make markets in such securities. 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.

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.

For valuation purposes, the last quoted prices of non-U.S. equity securities may be adjusted under the circumstances described below. If the fund determines that developments between the close of a foreign market and the close of the NYSE will, in its judgment, materially affect the value of some or all of its portfolio securities, the fund will adjust the previous closing prices to reflect what it believes to be the fair value of the securities as of the close of the NYSE. In deciding whether it is necessary to adjust closing prices to reflect fair value, the fund reviews a variety of factors, including developments in foreign markets, the performance of U.S. securities markets, and the performance of instruments trading in U.S. markets that represent foreign securities and baskets of foreign securities. A fund may also fair value securities in other situations, such as when a particular foreign market is closed but the fund is open. The fund uses outside pricing services to provide it with closing prices and information to evaluate and/or adjust those prices. The fund cannot predict how often it will use closing prices and how often it will determine it necessary to adjust those prices to reflect fair value. As a means of evaluating its security valuation process, the fund routinely compares closing prices, the next day’s opening prices in the same markets, and adjusted prices.

Valuation Inputs 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. For example, non-U.S. equity securities actively traded in foreign markets generally are reflected in Level 2 despite the availability of closing prices because the fund evaluates and determines whether those closing prices reflect fair value at the close of the NYSE or require adjustment, as described above. The following table summarizes the fund’s financial instruments, based on the inputs used to determine their values on June 30, 2010:

Following is a reconciliation of the fund’s Level 3 holdings for the six months ended June 30, 2010. Transfers into and out of Level 3 are reflected at the value of the financial instrument at the beginning of the period. 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, 2010, totaled ($33,244,000) for the six months ended June 30, 2010.

NOTE 3 - DERIVATIVE INSTRUMENTS

During the six months ended June 30, 2010, 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 and the right to reclaim or obligation to return collateral executed with the same counterparty under a master netting arrangement. As of June 30, 2010, the fund held equity futures with cumulative unrealized loss of $1,550,000; 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, 2010, the fund recognized $13,369,000 of realized gain on Futures and a $1,550,000 change in unrealized loss 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.

Futures Contracts 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 to manage exposure to interest rates, security prices, foreign currencies, and credit quality; as an efficient means of adjusting exposure to all or part of a target market; to enhance income; as a cash management tool; and/or to adjust credit exposure. 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, 2010, the fund’s exposure to futures, based on underlying notional amounts, was generally less than 1% of net assets.

NOTE 4 - OTHER INVESTMENT TRANSACTIONS

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.

Restricted Securities The fund may invest in securities that are subject to legal or contractual restrictions on resale. Prompt sale of such securities at an acceptable price may be difficult and may involve substantial delays and additional costs.

Securities Lending 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 fund 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. At June 30, 2010, there were no securities on loan.

Other Purchases and sales of portfolio securities other than short-term securities aggregated $1,621,245,000 and $1,572,711,000, respectively, for the six months ended June 30, 2010.

NOTE 5 - FEDERAL INCOME TAXES

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.

In accordance with federal tax regulations, the fund recognized capital losses in the current period for tax purposes that had been recognized in the prior fiscal year for financial reporting purposes. Such deferrals relate to net capital losses realized between November 1, 2009 and December 31, 2009, and totaled $918,000. The fund intends to retain realized gains to the extent of available capital loss carryforwards. As of December 31, 2009, the fund had $180,250,000 of unused capital loss carryforwards, which expire: $2,437,000 in fiscal 2010, and $177,813,000 in fiscal 2017.

At June 30, 2010, the cost of investments for federal income tax purposes was $4,539,066,000. Net unrealized gain aggregated $1,136,147,000 at period-end, of which $1,605,705,000 related to appreciated investments and $469,558,000 related to depreciated investments.

NOTE 6 - RELATED PARTY TRANSACTIONS

The fund is managed by T. Rowe Price Associates, Inc. (the manager or Price Associates), a wholly owned subsidiary of T. Rowe Price Group, Inc. The investment management agreement between the fund and the manager provides for an annual investment management fee, which is computed daily and paid monthly. The fee consists of an individual fund fee, equal to 0.35% of the fund’s average daily net assets, and a group fee. The group fee rate is calculated based on the combined net assets of certain mutual funds sponsored by Price Associates (the group) applied to a graduated fee schedule, with rates ranging from 0.48% for the first $1 billion of assets to 0.285% for assets in excess of $220 billion. The fund’s group fee is determined by applying the group fee rate to the fund’s average daily net assets. At June 30, 2010, the effective annual group fee rate was 0.30%.

In addition, the fund has entered into service agreements with Price Associates and two wholly owned subsidiaries of Price Associates (collectively, Price). Price Associates computes the daily share price and provides certain other administrative services to the fund. T. Rowe Price Services, Inc., provides shareholder and administrative services in its capacity as the fund’s transfer and dividend disbursing agent. T. Rowe Price Retirement Plan Services, Inc., provides subaccounting and recordkeeping services for certain retirement accounts invested in the fund. For the six months ended June 30, 2010, expenses incurred pursuant to these service agreements were $57,000 for Price Associates; $817,000 for T. Rowe Price Services, Inc.; and $1,458,000 for T. Rowe Price Retirement Plan Services, Inc. The total amount payable at period-end pursuant to these service agreements is reflected as Due to Affiliates in the accompanying financial statements.

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 borne by the fund in proportion to the average daily value of its shares owned by the college savings plan. For the six months ended June 30, 2010, the fund was charged $98,000 for shareholder servicing costs related to the college savings plans, of which $70,000 was for services provided by Price. The amount payable at period-end pursuant to this agreement is reflected as Due to Affiliates in the accompanying financial statements. At June 30, 2010, approximately 2% of the outstanding shares of the fund were held by college savings plans.

The fund is also one of several mutual funds sponsored by Price Associates (underlying Price funds) in which the T. Rowe Price Spectrum Funds (Spectrum Funds) and T. Rowe Price Retirement Funds (Retirement Funds) may invest. Neither the Spectrum Funds nor the Retirement Funds invest in the underlying Price funds for the purpose of exercising management or control. Pursuant to separate special servicing agreements, expenses associated with the operation of the Spectrum and Retirement Funds are borne by each underlying Price fund to the extent of estimated savings to it and in proportion to the average daily value of its shares owned by the Spectrum and Retirement Funds, respectively. Expenses allocated under these agreements are reflected as shareholder servicing expenses in the accompanying financial statements. For the six months ended June 30, 2010, the fund was allocated $64,000 of Spectrum Funds’ expenses and $780,000 of Retirement Funds’ expenses. Of these amounts, $531,000 related to services provided by Price. The amount payable at period-end pursuant to this agreement is reflected as Due to Affiliates in the accompanying financial statements. At June 30, 2010, approximately 1% of the outstanding shares of the fund were held by the Spectrum Funds and 12% were held by the Retirement Funds.

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.

As of June 30, 2010, T. Rowe Price Group, Inc., and/or its wholly owned subsidiaries owned 156,889 shares of the fund, representing less than 1% of the fund’s net assets.

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 Web site, www.sec.gov. The description of our proxy voting policies and procedures is also available on our Web site, www.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 Web site and through the SEC’s Web site. To access it through our Web site, 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 Web site (www.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, 2010, the fund’s Board of Directors (Board) unanimously approved the continuation of the investment advisory contract (Contract) between the fund and its investment manager, T. Rowe Price Associates, Inc. (Adviser). The Board considered a variety of factors in connection with its review of the Contract, also taking into account information provided by the Adviser during the course of the year, as discussed below:

Services Provided by the Adviser
The Board considered the nature, quality, and extent of the services provided to the fund by the Adviser. 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 Adviser’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 Adviser.

Investment Performance of the Fund
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 severity of the market turmoil during 2008 and 2009, the Board concluded that the fund’s performance was satisfactory.

Costs, Benefits, Profits, and Economies of Scale
The Board reviewed detailed information regarding the revenues received by the Adviser under the Contract and other benefits that the Adviser (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 Adviser may receive some benefit from its soft-dollar arrangements pursuant to which it receives research 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 Adviser and its affiliates from advising T. Rowe Price mutual funds, as well as estimates of the gross profits realized from managing the fund in particular. The Board concluded that the Adviser’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 Adviser. Under the Contract, the fund pays a fee to the Adviser composed of two components—a group fee rate based on the aggregate assets of certain T. Rowe Price mutual funds (including the fund) that declines at certain asset levels and an individual fund fee rate that is assessed on the assets of the fund. The Board concluded that the advisory fee structure for the fund continued to provide for a reasonable sharing of benefits from any economies of scale with the fund’s investors.

Fees
The Board reviewed the fund’s management fee rate, operating expenses, and total expense ratio and compared them 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 above the median for certain groups of comparable funds but at or below the median for other groups of comparable funds. The information also indicated that the fund’s total expense ratio was below the median for comparable funds. The Board also reviewed the fee schedules for institutional accounts of the Adviser and its affiliates with smaller mandates. Management informed the Board that the Adviser’s responsibilities for institutional accounts are more limited than its responsibilities for the fund and other T. Rowe Price mutual funds that it or its affiliates advise and that the Adviser 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 accounts. On the basis of the information provided, the Board concluded that the fees paid by the fund under the Contract were reasonable.

Approval of the Contract
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 New Horizons Fund, Inc.
By	/s/ Edward C. Bernard
	Edward C. Bernard
	Principal Executive Officer
Date	August 17, 2010
	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, 2010
By	/s/ Gregory K. Hinkle
	Gregory K. Hinkle
	Principal Financial Officer
Date	August 17, 2010

EX-99.CERT

Item 12(a)(2).

CERTIFICATIONS 

I, Edward C. Bernard, certify that:
1.	I have reviewed this report on Form N-CSR of T. Rowe Price New Horizons Fund;
2.	Based on my knowledge, this report does not contain any untrue statement of a material fact or omit
	to state a material fact necessary to make the statements made, in light of the circumstances under
	which such statements were made, not misleading with respect to the period covered by this report;
3.	Based on my knowledge, the financial statements, and other financial information included in this
	report, fairly present in all material respects the financial condition, results of operations, changes in
	net assets, and cash flows (if the financial statements are required to include a statement of cash
	flows) of the registrant as of, and for, the periods presented in this report;
4.	The registrant's other certifying officer(s) and I are responsible for establishing and maintaining
	disclosure controls and procedures (as defined in rule 30a-3(c) under the Investment Company Act
	of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the
	Investment Company Act of 1940) for the registrant and have:
	(a)	Designed such disclosure controls and procedures, or caused such disclosure controls and
		procedures to be designed under our supervision, to ensure that material information relating to
		the registrant, including its consolidated subsidiaries, is made known to us by others within those
		entities, particularly during the period in which this report is being prepared;
	(b)	Designed such internal control over financial reporting, or caused such internal control over
		financial reporting to be designed under our supervision, to provide reasonable assurance
		regarding the reliability of financial reporting and the preparation of financial statements for
		external purposes in accordance with generally accepted accounting principles;
	(c)	Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in
		this report our conclusions about the effectiveness of the disclosure controls and procedures, as of
		a date within 90 days prior to the filing date of this report based on such evaluation; and
	(d)	Disclosed in this report any change in the registrant’s internal control over financial reporting that
		occurred during the second fiscal quarter of the period covered by this report that has materially
		affected, or is reasonably likely to materially affect, the registrant’s internal control over financial
		reporting; and
5.	The registrant's other certifying officer(s) and I have disclosed to the registrant's auditors and the
	audit committee of the registrant's board of directors (or persons performing the equivalent
	functions):
	(a)	All significant deficiencies and material weaknesses in the design or operation of internal control
		over financial reporting which are reasonably likely to adversely affect the registrant's ability to
		record, process, summarize, and report financial information; and
	(b)	Any fraud, whether or not material, that involves management or other employees who have a
		significant role in the registrant's internal control over financial reporting.

Date:	August 17, 2010	/s/ Edward C. Bernard
		Edward C. Bernard
		Principal Executive Officer

CERTIFICATIONS 

I, Gregory K. Hinkle, certify that:
1.	I have reviewed this report on Form N-CSR of T. Rowe Price New Horizons Fund;
2.	Based on my knowledge, this report does not contain any untrue statement of a material fact or omit
	to state a material fact necessary to make the statements made, in light of the circumstances under
	which such statements were made, not misleading with respect to the period covered by this report;
3.	Based on my knowledge, the financial statements, and other financial information included in this
	report, fairly present in all material respects the financial condition, results of operations, changes in
	net assets, and cash flows (if the financial statements are required to include a statement of cash
	flows) of the registrant as of, and for, the periods presented in this report;
4.	The registrant's other certifying officer(s) and I are responsible for establishing and maintaining
	disclosure controls and procedures (as defined in rule 30a-3(c) under the Investment Company Act
	of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the
	Investment Company Act of 1940) for the registrant and have:
	(a)	Designed such disclosure controls and procedures, or caused such disclosure controls and
		procedures to be designed under our supervision, to ensure that material information relating to
		the registrant, including its consolidated subsidiaries, is made known to us by others within those
		entities, particularly during the period in which this report is being prepared;
	(b)	Designed such internal control over financial reporting, or caused such internal control over
		financial reporting to be designed under our supervision, to provide reasonable assurance
		regarding the reliability of financial reporting and the preparation of financial statements for
		external purposes in accordance with generally accepted accounting principles;
	(c)	Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in
		this report our conclusions about the effectiveness of the disclosure controls and procedures, as of
		a date within 90 days prior to the filing date of this report based on such evaluation; and
	(d)	Disclosed in this report any change in the registrant’s internal control over financial reporting that
		occurred during the second fiscal quarter of the period covered by this report that has materially
		affected, or is reasonably likely to materially affect, the registrant’s internal control over financial
		reporting; and
5.	The registrant's other certifying officer(s) and I have disclosed to the registrant's auditors and the
	audit committee of the registrant's board of directors (or persons performing the equivalent
	functions):
	(a)	All significant deficiencies and material weaknesses in the design or operation of internal control
		over financial reporting which are reasonably likely to adversely affect the registrant's ability to
		record, process, summarize, and report financial information; and
	(b)	Any fraud, whether or not material, that involves management or other employees who have a
		significant role in the registrant's internal control over financial reporting.

Date:	August 17, 2010	/s/ Gregory K. Hinkle
		Gregory K. Hinkle
		Principal Financial Officer

EX-99.906 CERT

Item 12(b).
CERTIFICATION UNDER SECTION 906 OF SARBANES-OXLEY ACT OF 2002
Name of Issuer: T. Rowe Price New Horizons Fund
In connection with the Report on Form N-CSR for the above named Issuer, the undersigned hereby
certifies, to the best of his knowledge, that:
1.	The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities
	Exchange Act of 1934;
2.	The information contained in the Report fairly presents, in all material respects, the financial
	condition and results of operations of the Issuer.
Date: August 17, 2010		/s/ Edward C. Bernard
		Edward C. Bernard
		Principal Executive Officer
Date: August 17, 2010		/s/ Gregory K. Hinkle
		Gregory K. Hinkle
		Principal Financial Officer