485BPOS

Registration Nos. 002-48848/811-2396

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933                          /X/

  Post-Effective Amendment No. 65                                                                        /X/

and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940 /X/

  Amendment No. 40                                                                                               /X/

T. ROWE PRICE NEW INCOME FUND, INC.

Exact Name of Registrant as Specified in Charter

100 East Pratt Street, Baltimore, Maryland 21202

Address of Principal Executive Offices

410-345-2000

Registrant’s Telephone Number, Including Area Code

David Oestreicher

100 East Pratt Street, Baltimore, Maryland 21202

Name and Address of Agent for Service

            It is proposed that this filing will become effective (check appropriate box):

/X/        Immediately upon filing pursuant to paragraph (b)

//          On (date) pursuant to paragraph (b)

//          60 days after filing pursuant to paragraph (a)(1)

//          On (date) pursuant to paragraph (a)(1)

//          75 days after filing pursuant to paragraph (a)(2)

//          On (date) pursuant to paragraph (a)(2) of Rule 485

            If appropriate, check the following box:

//          This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

Page 2

EXHIBITS

Exhibit	Exhibit No.
XBRL Instance Document	EX-101.INS
XBRL Taxonomy Extension Schema Document	EX-101.SCH
XBRL Taxonomy Extension Calculation Linkbase Document	EX-101.CAL
XBRL Taxonomy Extension Definition Linkbase Document	EX-101.DEF
XBRL Taxonomy Extension Labels Linkbase Document	EX-101.LAB
XBRL Taxonomy Extension Presentation Linkbase Document	EX-101.PRE

Page 3

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant certifies that it meets all of the requirements for effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City of Baltimore, State of Maryland, this October 20, 2011.

               T. ROWE PRICE NEW INCOME FUND, INC.

               /s/Edward C. Bernard

By:          Edward C. Bernard

               Chairman of the Board

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated:

Signature	Title	Date
/s/Edward C. Bernard	Chairman of the Board	October 20, 2011
Edward C. Bernard	(Chief Executive Officer)
/s/Gregory K. Hinkle	Treasurer (Chief	October 20, 2011
Gregory K. Hinkle	Financial Officer)
*	Director	October 20, 2011
William R. Brody
*	Director	October 20, 2011
Jeremiah E. Casey
*	Director	October 20, 2011
Anthony W. Deering
*	Director	October 20, 2011
Donald W. Dick, Jr.
/s/Michael C. Gitlin	Director	October 20, 2011
Michael C. Gitlin
*	Director	October 20, 2011
Karen N. Horn
*	Director	October 20, 2011
Theo C. Rodgers
*	Director	October 20, 2011
John G. Schreiber
*	Director	October 20, 2011
Mark. R. Tercek
*/s/David Oestreicher	Vice President and	October 20, 2011
David Oestreicher	Attorney-In-Fact

Page 4

T. ROWE PRICE BALANCED FUND, INC.

T. ROWE PRICE BLUE CHIP GROWTH FUND, INC.

T. ROWE PRICE CALIFORNIA TAX-FREE INCOME TRUST

T. ROWE PRICE CAPITAL APPRECIATION FUND

T. ROWE PRICE CAPITAL OPPORTUNITY FUND, INC.

T. ROWE PRICE CORPORATE INCOME FUND, INC.

T. ROWE PRICE DIVERSIFIED MID-CAP GROWTH FUND, INC.

T. ROWE PRICE DIVERSIFIED SMALL-CAP GROWTH FUND, INC.

T. ROWE PRICE DIVIDEND GROWTH FUND, INC.

T. ROWE PRICE EQUITY INCOME FUND

T. ROWE PRICE EQUITY SERIES, INC.

T. ROWE PRICE FINANCIAL SERVICES FUND, INC.

T. ROWE PRICE FIXED INCOME SERIES, INC.

T. ROWE PRICE FLOATING RATE FUND, INC.

T. ROWE PRICE GLOBAL REAL ESTATE FUND, INC.

T. ROWE PRICE GLOBAL TECHNOLOGY FUND, INC.

T. ROWE PRICE GNMA FUND

T. ROWE PRICE GROWTH & INCOME FUND, INC.

T. ROWE PRICE GROWTH STOCK FUND, INC.

T. ROWE PRICE HEALTH SCIENCES FUND, INC.

T. ROWE PRICE HIGH YIELD FUND, INC.

T. ROWE PRICE INDEX TRUST, INC.

T. ROWE PRICE INFLATION FOCUSED BOND FUND, INC.

T. ROWE PRICE INFLATION PROTECTED BOND FUND, INC.

T. ROWE PRICE INSTITUTIONAL EQUITY FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INCOME FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL INDEX FUND, INC.

T. ROWE PRICE INTERNATIONAL SERIES, INC.

T. ROWE PRICE MEDIA & TELECOMMUNICATIONS FUND, INC.

T. ROWE PRICE MID-CAP GROWTH FUND, INC.

T. ROWE PRICE MID-CAP VALUE FUND, INC.

T. ROWE PRICE NEW AMERICA GROWTH FUND
T. ROWE PRICE NEW ERA FUND, INC.

T. ROWE PRICE NEW HORIZONS FUND, INC.

T. ROWE PRICE NEW INCOME FUND, INC.

T. ROWE PRICE PERSONAL STRATEGY FUNDS, INC.

T. ROWE PRICE PRIME RESERVE FUND, INC.

T. ROWE PRICE REAL ASSETS FUND, INC.

T. ROWE PRICE REAL ESTATE FUND, INC.

T. ROWE PRICE RESERVE INVESTMENT FUNDS, INC.

T. ROWE PRICE RETIREMENT FUNDS, INC.

T. ROWE PRICE SCIENCE & TECHNOLOGY FUND, INC.

T. ROWE PRICE SHORT-TERM BOND FUND, INC.

T. ROWE PRICE SMALL-CAP STOCK FUND, INC.

T. ROWE PRICE SMALL-CAP VALUE FUND, INC.

T. ROWE PRICE SPECTRUM FUND, INC.

T. ROWE PRICE STATE TAX-FREE INCOME TRUST

T. ROWE PRICE STRATEGIC INCOME FUND, INC.

Page 5

T. ROWE PRICE SUMMIT FUNDS, INC.

T. ROWE PRICE SUMMIT MUNICIPAL FUNDS, INC.

T. ROWE PRICE TAX-EFFICIENT FUNDS, INC.

T. ROWE PRICE TAX-EXEMPT MONEY FUND, INC.

T. ROWE PRICE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE TAX-FREE INCOME FUND, INC.

T. ROWE PRICE TAX-FREE SHORT-INTERMEDIATE FUND, INC.

T. ROWE PRICE U.S. BOND INDEX FUND, INC.

T. ROWE PRICE U.S. LARGE-CAP CORE FUND, INC.

T. ROWE PRICE U.S. TREASURY FUNDS, INC.

T. ROWE PRICE VALUE FUND, INC.

POWER OF ATTORNEY

                RESOLVED, that the Corporation does hereby constitute and authorize Edward C. Bernard, Margery K. Neale and David Oestreicher, and each of them individually, their true and lawful attorneys and agents to take any and all action and execute any and all instruments which said attorneys and agents may deem necessary or advisable to enable the Corporation/Trust to comply with the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, and any rules, regulations, orders or other requirements of the United States Securities and Exchange Commission thereunder, in connection with the registration under the Securities Act of 1933, as amended, of shares of the Corporation/Trust, to be offered by the Corporation/Trust, and the registration of the Corporation/Trust under the Investment Company Act of 1940, as amended, including specifically, but without limitation of the foregoing, power and authority to sign the name of the Corporation/Trust on its behalf, and to sign the names of each of such directors/trustees and officers on his behalf as such director/trustee or officer to any (i) Registration Statement on Form N-1A or N-14 of the Corporation/Trust filed with the Securities and Exchange Commission under the Securities Act of 1933, as amended; (ii) Registration Statement on Form N-1A or N-14 of the Corporation/Trust under the Investment Company Act of 1940, as amended; (iii) amendment or supplement (including, but not limited to, Post-Effective Amendments adding additional series or classes of the Corporation/ Trust) to said Registration Statement; and (iv) instruments or documents filed or to be filed as a part of or in connection with such Registration Statement, including Articles Supplementary, Articles of Amendment, and other instruments with respect to the Articles of Incorporation or Master Trust Agreement of the Corporation/Trust.

                IN WITNESS WHEREOF, the above named Corporations/Trusts have caused these presents to be signed and the same attested by its Secretary, each thereunto duly authorized by its Board of Directors/Trustees, and each of the undersigned has hereunto set his hand and seal as of the day set opposite his name.

ALL CORPORATIONS/TRUSTS
/s/Edward C. Bernard Edward C. Bernard	Chairman of the Board (Principal Executive Officer) Director/Trustee	April 20, 2011
/s/Gregory K. Hinkle Gregory K. Hinkle	Treasurer (Principal Financial Officer)	April 20, 2011
/s/William R. Brody William R. Brody	Director/Trustee	April 20, 2011
/s/Jeremiah E. Casey Jeremiah E. Casey	Director/Trustee	April 20, 2011
/s/Anthony W. Deering Anthony W. Deering	Director/Trustee	April 20, 2011
/s/Donald W. Dick, Jr. Donald W. Dick, Jr.	Director/Trustee	April 20, 2011
/s/Karen N. Horn Karen N. Horn	Director/Trustee	April 20, 2011
/s/Theo C. Rodgers Theo C. Rodgers	Director/Trustee	April 20, 2011
/s/John G. Schreiber John G. Schreiber	Director/Trustee	April 20, 2011
/s/Mark R. Tercek Mark R. Tercek	Director/Trustee	April 20, 2011

Page 6

(Signatures Continued)

Page 7

MICHAEL C. GITLIN, Director/Trustee

T. ROWE PRICE CALIFORNIA TAX-FREE INCOME TRUST

T. ROWE PRICE CORPORATE INCOME FUND, INC.

T. ROWE PRICE FIXED INCOME SERIES, INC.

T. ROWE PRICE GNMA FUND

T. ROWE PRICE HIGH YIELD FUND, INC.

T. ROWE PRICE INSTITUTIONAL INCOME FUNDS, INC.

T. ROWE PRICE INFLATION FOCUSED BOND FUND, INC.

T. ROWE PRICE INFLATION PROTECTED BOND FUND, INC.

T. ROWE PRICE NEW INCOME FUND, INC.

T. ROWE PRICE PRIME RESERVE FUND, INC.

T. ROWE PRICE RESERVE INVESTMENT FUNDS, INC.

T. ROWE PRICE SHORT-TERM BOND FUND, INC.

T. ROWE PRICE STATE TAX-FREE INCOME TRUST

T. ROWE PRICE STRATEGIC INCOME FUND, INC.

T. ROWE PRICE SUMMIT FUNDS, INC.

T. ROWE PRICE SUMMIT MUNICIPAL FUNDS, INC.

T. ROWE PRICE TAX-EXEMPT MONEY FUND, INC.

T. ROWE PRICE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE TAX-FREE INCOME FUND, INC.

T. ROWE PRICE TAX-FREE SHORT-INTERMEDIATE FUND, INC.

T. ROWE PRICE U.S. BOND INDEX FUND, INC.

T. ROWE PRICE U.S. TREASURY FUNDS, INC.

/s/Michael C. Gitlin Michael C. Gitlin April 20, 2011

(Signatures Continued)

Page 8

JOHN H. LAPORTE, Director/Trustee

T. ROWE PRICE CAPITAL OPPORTUNITY FUND, INC.

T. ROWE PRICE DIVERSIFIED MID-CAP GROWTH FUND, INC.

T. ROWE PRICE EQUITY SERIES, INC.

T. ROWE PRICE NEW AMERICA GROWTH FUND

T. ROWE PRICE SCIENCE & TECHNOLOGY FUND, INC.

T. ROWE PRICE SMALL-CAP STOCK FUND, INC.

T. ROWE PRICE SMALL-CAP VALUE FUND, INC.

JOHN H. LAPORTE, Director and Vice President

T. ROWE PRICE DIVERSIFIED SMALL-CAP GROWTH FUND, INC.

T. ROWE PRICE HEALTH SCIENCES FUND, INC.

T. ROWE PRICE NEW HORIZONS FUND, INC.

/s/John H. Laporte John H. Laporte April 20, 2011

(Signatures Continued)

Page 9

BRIAN C. ROGERS, Director/Trustee

T. ROWE PRICE BALANCED FUND, INC.

T. ROWE PRICE BLUE CHIP GROWTH FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION FUND

T. ROWE PRICE DIVIDEND GROWTH FUND, INC.

T. ROWE PRICE FINANCIAL SERVICES FUND, INC.

T. ROWE PRICE GLOBAL REAL ESTATE FUND, INC.

T. ROWE PRICE GLOBAL TECHNOLOGY FUND, INC.

T. ROWE PRICE GROWTH & INCOME FUND, INC.

T. ROWE PRICE GROWTH STOCK FUND, INC.

T. ROWE INDEX TRUST, INC.

T. ROWE PRICE INSTITUTIONAL INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL INDEX FUND, INC.

T. ROWE PRICE INTERNATIONAL SERIES, INC.

T. ROWE PRICE MEDIA & TELECOMMUNICATIONS FUND, INC.

T. ROWE PRICE MID-CAP GROWTH FUND, INC.

T. ROWE PRICE MID-CAP VALUE FUND, INC.

T. ROWE PRICE NEW ERA FUND, INC.

T. ROWE PRICE REAL ASSETS FUND, INC.

T. ROWE PRICE REAL ESTATE FUND, INC.

T. ROWE PRICE TAX-EFFICIENT FUNDS, INC.

T. ROWE PRICE U.S. LARGE-CAP CORE FUND, INC.

BRIAN C. ROGERS, Director/Trustee and President

T. ROWE PRICE EQUITY INCOME FUND

T. ROWE PRICE INSTITUTIONAL EQUITY FUNDS, INC.

BRIAN C. ROGERS, Director/Trustee and Vice President

T. ROWE PRICE PERSONAL STRATEGY FUNDS, INC.

T. ROWE PRICE RETIREMENT FUNDS, INC.

T. ROWE PRICE SPECTRUM FUND, INC.

T. ROWE PRICE VALUE FUND, INC.

/s/Brian C. Rogers Brian C. Rogers April 20, 2011

(Signatures Continued)

Page 10

ATTEST:

/s/Patricia B. Lippert

Patricia B. Lippert, Secretary

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Prospectus Date	rr_ProspectusDate	Oct. 01, 2011

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	May 31, 2011
Registrant Name	dei_EntityRegistrantName	T. Rowe Price New Income Fund, Inc.
Central Index Key	dei_EntityCentralIndexKey	0000080249
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Sep. 27, 2011
Document Effective Date	dei_DocumentEffectiveDate	Oct. 01, 2011
Prospectus Date	rr_ProspectusDate	Oct. 01, 2011

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price New Income Fund, Inc.

Prospectus Date

rr_ProspectusDate

Oct. 01, 2011

Investor Class | T. Rowe Price New Income Fund, Inc. | T. Rowe Price New Income Fund, Inc.

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load)

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Redemption fee

rr_RedemptionFeeOverRedemption

none

Maximum account fee

rr_MaximumAccountFee

20

^[1]

Management fees

rr_ManagementFeesOverAssets

0.45%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.18%

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.03%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.66%

Fee waiver/expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

0.02%

^[2]

Total annual fund operating expenses after fee waiver/expense reimbursement

rr_NetExpensesOverAssets

0.64%

^[3]

1 year

rr_ExpenseExampleYear01

65

3 years

rr_ExpenseExampleYear03

205

5 years

rr_ExpenseExampleYear05

357

10 years

rr_ExpenseExampleYear10

798

Annual Return 2001

rr_AnnualReturn2001

8.15%

Annual Return 2002

rr_AnnualReturn2002

7.48%

Annual Return 2003

rr_AnnualReturn2003

5.62%

Annual Return 2004

rr_AnnualReturn2004

4.60%

Annual Return 2005

rr_AnnualReturn2005

2.85%

Annual Return 2006

rr_AnnualReturn2006

4.13%

Annual Return 2007

rr_AnnualReturn2007

6.33%

Annual Return 2008

rr_AnnualReturn2008

1.41%

Annual Return 2009

rr_AnnualReturn2009

12.33%

Annual Return 2010

rr_AnnualReturn2010

7.16%

Year to Date Return, Label

rr_YearToDateReturnLabel

The fund's return for the six months ended 6/30/11

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2011

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.27%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

5.07%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2004

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(2.36%)

1 Year

rr_AverageAnnualReturnYear01

7.16%

5 Years

rr_AverageAnnualReturnYear05

6.21%

10 Years

rr_AverageAnnualReturnYear10

5.97%

Investor Class | T. Rowe Price New Income Fund, Inc. | T. Rowe Price New Income Fund, Inc. | Returns after taxes on distributions

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

5.55%

5 Years

rr_AverageAnnualReturnYear05

4.77%

10 Years

rr_AverageAnnualReturnYear10

4.38%

Investor Class | T. Rowe Price New Income Fund, Inc. | T. Rowe Price New Income Fund, Inc. | Returns after taxes on distributions and sale of fund shares

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

4.73%

5 Years

rr_AverageAnnualReturnYear05

4.60%

10 Years

rr_AverageAnnualReturnYear10

4.23%

Investor Class | T. Rowe Price New Income Fund, Inc.

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. Rowe Price

New Income Fund

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks the highest level of income consistent with the preservation of capital over time by investing primarily in marketable debt securities.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

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

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund

Shareholder fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

 Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 110.7% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

110.70%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

The figure shown under "Total annual fund operating expenses after fee waiver/expense reimbursement" does not match the "Ratio of expenses to average net assets" shown in the Financial Highlights table, as that figure does not include acquired fund fees and expenses

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

In seeking income and capital preservation, the fund pursues a total return strategy. Active management of the portfolio can result in bonds being sold at gains or losses. However, over the long term, the fund seeks to achieve its objective by investing primarily in income-producing securities that possess what the fund believes are favorable total return (income plus changes in principal) characteristics.

The fund will invest at least 80% of its total assets in income-producing securities, which may include, but are not limited to, U.S. government and agency obligations, mortgage- and asset-backed securities, corporate bonds, foreign securities, collateralized mortgage obligations, Treasury inflation protected securities, and others, including, on occasion, equities.

Eighty percent (80%) of the debt securities purchased by the fund will be rated investment grade (AAA, AA, A, BBB, or an equivalent rating) by each of the major credit rating agencies (Standard & Poor's, Moody's, and Fitch) that have assigned a rating to the security or, if unrated, deemed to be of investment-grade quality by T. Rowe Price. Up to 15% of the fund's total assets may be invested in "split-rated securities," which are securities that have been rated investment grade by at least one rating agency but below investment grade by another rating agency. In addition, the fund may invest up to 5% of its total assets in securities that have received below investment-grade ratings from each of the rating agencies that have assigned ratings to the securities or, if unrated, deemed to be below investment-grade quality by T. Rowe Price.

The fund has considerable flexibility in seeking high yields. There are no maturity restrictions, so the fund can purchase longer-term bonds, which tend to have higher yields than shorter-term issues. However, the portfolio's weighted average maturity is expected to be between four and 15 years. In addition, when there is a large yield difference between the various quality levels, the fund may move down the credit scale and purchase lower-rated bonds with higher yields. When the difference is small or the outlook warrants, the fund may concentrate investments in higher-rated issues.

While most assets will typically be invested in bonds, the fund also invests in derivatives such as interest rate futures and forward currency exchange contracts inkeeping with the fund's objective .

The fund may sell holdings for a variety of reasons, such as to adjust the portfolio's average maturity, duration, or credit quality or to shift assets into and out of higher-yielding or lower-yielding securities or different sectors.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund's share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management riskThe fund is subject to the risk that the investment adviser's judgments about the attractiveness, value, or potential appreciation of the fund's investments may prove to be incorrect. If the securities selected and strategies employed by the fund fail to produce the intended results, the fund could underperform other funds with similar objectives and investment strategies.

Interest rate risk  This is the risk that a rise in interest rates will cause the price of a fixed rate debt security to fall. Generally, the longer the maturity of a security or weighted average maturity of a fund, the greater the interest rate risk.

Credit risk  This is the risk that an issuer of a debt security or counterparty to an over-the-counter derivative could suffer an adverse change in financial condition that results in a payment default, security downgrade, or inability to meet a financial obligation.

Liquidity risk  This is the risk that the fund may not be able to sell a holdingin a timely manner at a desired price.

Foreign investing risk  This is the risk that the fund's investments in foreign securities may be adversely affected by political and economic conditions overseas, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

Prepayment risk and extension riskPrepayment risk is the risk that the principal on mortgage-backed securities, other asset-backed securities or any fixed income security with an embedded call option may be prepaid at any time, which could reduce yield and market value. The rate of prepayments tends to increase as interest rates fall, which could cause the average maturity of the portfolio to shorten. Extension risk may result from a rise in interest rates, which tends to make mortgage-backed securities, asset-backed securities, and other callable fixed income securities more volatile.

Derivatives risk  To the extent the fund uses interest rate futures and forward currency exchange contracts, it is exposed to additional volatility in comparison toinvesting directly in bonds and other debt securities.Derivatives can be illiquid and difficult to value , may involve leverage so that small changes produce disproportionate losses for the fund, and instruments not traded on an exchange are subject to the risk that a counterparty to the transaction will fail to meet its obligations under the derivatives contract. The fund's principal use of derivatives involves the risk that anticipated interest rate movements and changes in currency values and currency exchange rates will not be accurately predicted, which could significantly harm the fund's performance.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund's share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index. The fund's past performance (before and after taxes) is not necessarily an indication of future performance.

The fund can also experience short-term performance swings, as shown by the best and worst calendar quarter returns during the years depicted.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

1-800-225-5132

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

troweprice.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund's past performance (before and after taxes) is not necessarily an indication of future performance.

Bar Chart [Heading]

rr_BarChartHeading

New Income Fund

Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return
Best Quarter	6/30/09	5.07%
Worst Quarter	6/30/04	-2.36%

The fund's return for the six months ended 6/30/11 was 2.27%.

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns

Periods ended

December 31, 2010

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or individual retirement account.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

In addition, the average annual total returns table shows hypothetical after-tax returns to suggest how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or individual retirement account.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com or may be obtained by calling 1-800-225-5132. 

Investor Class | T. Rowe Price New Income Fund, Inc. | Barclays Capital U.S. Aggregate Bond Index

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

6.54%

5 Years

rr_AverageAnnualReturnYear05

5.80%

10 Years

rr_AverageAnnualReturnYear10

5.84%

Investor Class | T. Rowe Price New Income Fund, Inc. | Lipper Corporate Debt Funds A-Rated Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

7.51%

5 Years

rr_AverageAnnualReturnYear05

4.78%

10 Years

rr_AverageAnnualReturnYear10

5.24%

[1] Subject to certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee.

[2] T. Rowe Price Associates, Inc. is required to permanently waive a portion of its management fee charged to the fund in an amount sufficient to fully offset any acquired fund fees and expenses related to investments in other T. Rowe Price mutual funds. The amount of the waiver will vary each fiscal year in proportion to the amount invested in other T. Rowe Price mutual funds. The T. Rowe Price funds would be required to seek regulatory approval in order to terminate this arrangement.

[3] The figure shown under "Total annual fund operating expenses after fee waiver/expense reimbursement" does not match the "Ratio of expenses to average net assets" shown in the Financial Highlights table, as that figure does not include acquired fund fees and expenses.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price New Income Fund, Inc.

Prospectus Date

rr_ProspectusDate

Oct. 01, 2011

Advisor Class | T. Rowe Price New Income Fund, Inc. | T. Rowe Price New Income Fund-Advisor Class

Risk/Return:

rr_RiskReturnAbstract

Management fees

rr_ManagementFeesOverAssets

0.45%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.17%

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.03%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.90%

Fee waiver/expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

0.02%

^[1]

Total annual fund operating expenses after fee waiver/expense reimbursement

rr_NetExpensesOverAssets

0.88%

^[2]

1 year

rr_ExpenseExampleYear01

90

3 years

rr_ExpenseExampleYear03

281

5 years

rr_ExpenseExampleYear05

488

10 years

rr_ExpenseExampleYear10

1,084

Annual Return 2003

rr_AnnualReturn2003

5.32%

Annual Return 2004

rr_AnnualReturn2004

4.48%

Annual Return 2005

rr_AnnualReturn2005

2.60%

Annual Return 2006

rr_AnnualReturn2006

3.77%

Annual Return 2007

rr_AnnualReturn2007

6.18%

Annual Return 2008

rr_AnnualReturn2008

1.16%

Annual Return 2009

rr_AnnualReturn2009

12.13%

Annual Return 2010

rr_AnnualReturn2010

6.84%

Year to Date Return, Label

rr_YearToDateReturnLabel

The fund's return for the six months ended 6/30/11

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2011

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.07%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

5.02%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2004

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(2.41%)

1 Year

rr_AverageAnnualReturnYear01

6.84%

5 Years

rr_AverageAnnualReturnYear05

5.95%

Since inception

rr_AverageAnnualReturnSinceInception

5.31%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2002

Advisor Class | T. Rowe Price New Income Fund, Inc. | T. Rowe Price New Income Fund-Advisor Class | Returns after taxes on distributions

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

5.30%

5 Years

rr_AverageAnnualReturnYear05

4.58%

Since inception

rr_AverageAnnualReturnSinceInception

3.93%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2002

Advisor Class | T. Rowe Price New Income Fund, Inc. | T. Rowe Price New Income Fund-Advisor Class | Returns after taxes on distributions and sale of fund shares

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

4.52%

5 Years

rr_AverageAnnualReturnYear05

4.41%

Since inception

rr_AverageAnnualReturnSinceInception

3.81%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2002

Advisor Class | T. Rowe Price New Income Fund, Inc.

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. Rowe Price

New Income Fund–Advisor Class

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks the highest level of income consistent with the preservation of capital over time by investing primarily in marketable debt securities.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

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

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Fees and Expenses of the Fund's Advisor Class

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 110.7% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

110.70%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

The figure shown under "Total annual fund operating expenses after fee waiver/expense reimbursement" does not match the "Ratio of expenses to average net assets" shown in the Financial Highlights table, as that figure does not include acquired fund fees and expenses

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

In seeking income and capital preservation, the fund pursues a total return strategy. Active management of the portfolio can result in bonds being sold at gains or losses. However, over the long term, the fund seeks to achieve its objective by investing primarily in income-producing securities that possess what the fund believes are favorable total return (income plus changes in principal) characteristics.

The fund will invest at least 80% of its total assets in income-producing securities, which may include, but are not limited to, U.S. government and agency obligations, mortgage- and asset-backed securities, corporate bonds, foreign securities, collateralized mortgage obligations, Treasury inflation protected securities, and others, including, on occasion, equities.

Eighty percent (80%) of the debt securities purchased by the fund will be rated investment grade (AAA, AA, A, BBB, or an equivalent rating) by each of the major credit rating agencies (Standard & Poor's, Moody's, and Fitch) that have assigned a rating to the security or, if unrated, deemed to be of investment-grade quality by T. Rowe Price. Up to 15% of the fund's total assets may be invested in "split-rated securities," which are securities that have been rated investment grade by at least one rating agency but below investment grade by another rating agency. In addition, the fund may invest up to 5% of its total assets in securities that have received below investment-grade ratings from each of the rating agencies that have assigned ratings to the securities or, if unrated, deemed to be below investment-grade quality by T. Rowe Price.

The fund has considerable flexibility in seeking high yields. There are no maturity restrictions, so the fund can purchase longer-term bonds, which tend to have higher yields than shorter-term issues. However, the portfolio's weighted average maturity is expected to be between four and 15 years. In addition, when there is a large yield difference between the various quality levels, the fund may move down the credit scale and purchase lower-rated bonds with higher yields. When the difference is small or the outlook warrants, the fund may concentrate investments in higher-rated issues.

While most assets will typically be invested in bonds, the fund also invests in derivatives such as interest rate futures and forward currency exchange contracts inkeeping with the fund's objective s.

The fund may sell holdings for a variety of reasons, such as to adjust the portfolio's average maturity, duration, or credit quality or to shift assets into and out of higher-yielding or lower-yielding securities or different sectors.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund's share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management riskThe fund is subject to the risk that the investment adviser's judgments about the attractiveness, value, or potential appreciation of the fund's investments may prove to be incorrect. If the securities selected and strategies employed by the fund fail to produce the intended results, the fund could underperform other funds with similar objectives and investment strategies.

Interest rate risk  This is the risk that a rise in interest rates will cause the price of a fixed rate debt security to fall. Generally, the longer the maturity of a security or weighted average maturity of a fund, the greater the interest rate risk.

Credit risk  This is the risk that an issuer of a debt security or counterparty to an over-the-counter derivative could suffer an adverse change in financial condition that results in a payment default, security downgrade, or inability to meet a financial obligation.

Liquidity risk  This is the risk that the fund may not be able to sell a holdingin a timely manner at a desired price.

Foreign investing risk  This is the risk that the fund's investments in foreign securities may be adversely affected by political and economic conditions overseas, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

Prepayment risk and extension riskPrepayment risk is the risk that the principal on mortgage-backed securities, other asset-backed securities or any fixed income security with an embedded call option may be prepaid at any time, which could reduce yield and market value. The rate of prepayments tends to increase as interest rates fall, which could cause the average maturity of the portfolio to shorten. Extension risk may result from a rise in interest rates, which tends to make mortgage-backed securities, asset-backed securities, and other callable fixed income securities more volatile.

Derivatives risk  To the extent the fund uses interest rate futures and forward currency exchange contracts, it is exposed to additional volatility in comparison toinvesting directly in bonds and other debt securities.Derivatives can be illiquid and difficult to value , may involve leverage so that small changes produce disproportionate losses for the fund, and instruments not traded on an exchange are subject to the risk that a counterparty to the transaction will fail to meet its obligations under the derivatives contract. The fund's principal use of derivatives involves the risk that anticipated interest rate movements and changes in currency values and currency exchange rates will not be accurately predicted, which could significantly harm the fund's performance.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund's share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index.The fund's past performance (before and after taxes) is not necessarily an indication of future performance.

The fund can also experience short-term performance swings, as shown by the best and worst calendar quarter returns during the years depicted.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

1-800-638-8790

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

troweprice.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund's past performance (before and after taxes) is not necessarily an indication of future performance.

Bar Chart [Heading]

rr_BarChartHeading

New Income Fund - Advisor Class

Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return
Best Quarter	6/30/09	5.02%
Worst Quarter	6/30/04	-2.41%

The fund's return for the six months ended 6/30/11 was 2.07%.

Performance Table Heading

rr_PerformanceTableHeading

 Average Annual Total Returns

Periods ended

December 31, 2010

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or individual retirement account.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

In addition, the average annual total returns table shows hypothetical after-tax returns to suggest how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or individual retirement account.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com or may be obtained by calling 1-800-638-8790. 

Advisor Class | T. Rowe Price New Income Fund, Inc. | Barclays Capital U.S. Aggregate Bond Index

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

6.54%

5 Years

rr_AverageAnnualReturnYear05

5.80%

Since inception

rr_AverageAnnualReturnSinceInception

5.02%

Advisor Class | T. Rowe Price New Income Fund, Inc. | Lipper Corporate Debt Funds A-Rated Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

7.51%

5 Years

rr_AverageAnnualReturnYear05

4.78%

Since inception

rr_AverageAnnualReturnSinceInception

4.63%

[1] T. Rowe Price Associates, Inc. is required to permanently waive a portion of its management fee charged to the fund in an amount sufficient to fully offset any acquired fund fees and expenses related to investments in other T. Rowe Price mutual funds. The amount of the waiver will vary each fiscal year in proportion to the amount invested in other T. Rowe Price mutual funds. The T. Rowe Price funds would be required to seek regulatory approval in order to terminate this arrangement.

[2] The figure shown under "Total annual fund operating expenses after fee waiver/expense reimbursement" does not match the "Ratio of expenses to average net assets" shown in the Financial Highlights table, as that figure does not include acquired fund fees and expenses.

XML

Advisor Class | T. Rowe Price New Income Fund, Inc.

T. Rowe Price

New Income Fund–Advisor Class

Investment Objective

The fund seeks the highest level of income consistent with the preservation of capital over time by investing primarily in marketable debt securities.

Fees and Expenses

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

Fees and Expenses of the Fund's Advisor Class

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Annual Fund Operating Expenses -		Advisor Class T. Rowe Price New Income Fund, Inc. T. Rowe Price New Income Fund-Advisor Class
Management fees		0.45%
Distribution and service (12b-1) fees		0.25%
Other expenses		0.17%
Acquired fund fees and expenses		0.03%
Total annual fund operating expenses		0.90%
Fee waiver/expense reimbursement	[1]	0.02%
Total annual fund operating expenses after fee waiver/expense reimbursement	[2]	0.88%

Example

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

Expense Example - (USD $)	1 year	3 years	5 years	10 years
Advisor Class T. Rowe Price New Income Fund, Inc. T. Rowe Price New Income Fund-Advisor Class	90	281	488	1,084

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 110.7% of the average value of its portfolio.

Investments, Risks, and Performance

Principal Investment Strategies

In seeking income and capital preservation, the fund pursues a total return strategy. Active management of the portfolio can result in bonds being sold at gains or losses. However, over the long term, the fund seeks to achieve its objective by investing primarily in income-producing securities that possess what the fund believes are favorable total return (income plus changes in principal) characteristics.

The fund will invest at least 80% of its total assets in income-producing securities, which may include, but are not limited to, U.S. government and agency obligations, mortgage- and asset-backed securities, corporate bonds, foreign securities, collateralized mortgage obligations, Treasury inflation protected securities, and others, including, on occasion, equities.

Eighty percent (80%) of the debt securities purchased by the fund will be rated investment grade (AAA, AA, A, BBB, or an equivalent rating) by each of the major credit rating agencies (Standard & Poor's, Moody's, and Fitch) that have assigned a rating to the security or, if unrated, deemed to be of investment-grade quality by T. Rowe Price. Up to 15% of the fund's total assets may be invested in "split-rated securities," which are securities that have been rated investment grade by at least one rating agency but below investment grade by another rating agency. In addition, the fund may invest up to 5% of its total assets in securities that have received below investment-grade ratings from each of the rating agencies that have assigned ratings to the securities or, if unrated, deemed to be below investment-grade quality by T. Rowe Price.

The fund has considerable flexibility in seeking high yields. There are no maturity restrictions, so the fund can purchase longer-term bonds, which tend to have higher yields than shorter-term issues. However, the portfolio's weighted average maturity is expected to be between four and 15 years. In addition, when there is a large yield difference between the various quality levels, the fund may move down the credit scale and purchase lower-rated bonds with higher yields. When the difference is small or the outlook warrants, the fund may concentrate investments in higher-rated issues.

While most assets will typically be invested in bonds, the fund also invests in derivatives such as interest rate futures and forward currency exchange contracts inkeeping with the fund's objective s.

The fund may sell holdings for a variety of reasons, such as to adjust the portfolio's average maturity, duration, or credit quality or to shift assets into and out of higher-yielding or lower-yielding securities or different sectors.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund's share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management riskThe fund is subject to the risk that the investment adviser's judgments about the attractiveness, value, or potential appreciation of the fund's investments may prove to be incorrect. If the securities selected and strategies employed by the fund fail to produce the intended results, the fund could underperform other funds with similar objectives and investment strategies.

Interest rate risk  This is the risk that a rise in interest rates will cause the price of a fixed rate debt security to fall. Generally, the longer the maturity of a security or weighted average maturity of a fund, the greater the interest rate risk.

Credit risk  This is the risk that an issuer of a debt security or counterparty to an over-the-counter derivative could suffer an adverse change in financial condition that results in a payment default, security downgrade, or inability to meet a financial obligation.

Liquidity risk  This is the risk that the fund may not be able to sell a holdingin a timely manner at a desired price.

Foreign investing risk  This is the risk that the fund's investments in foreign securities may be adversely affected by political and economic conditions overseas, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

Prepayment risk and extension riskPrepayment risk is the risk that the principal on mortgage-backed securities, other asset-backed securities or any fixed income security with an embedded call option may be prepaid at any time, which could reduce yield and market value. The rate of prepayments tends to increase as interest rates fall, which could cause the average maturity of the portfolio to shorten. Extension risk may result from a rise in interest rates, which tends to make mortgage-backed securities, asset-backed securities, and other callable fixed income securities more volatile.

Derivatives risk  To the extent the fund uses interest rate futures and forward currency exchange contracts, it is exposed to additional volatility in comparison toinvesting directly in bonds and other debt securities.Derivatives can be illiquid and difficult to value , may involve leverage so that small changes produce disproportionate losses for the fund, and instruments not traded on an exchange are subject to the risk that a counterparty to the transaction will fail to meet its obligations under the derivatives contract. The fund's principal use of derivatives involves the risk that anticipated interest rate movements and changes in currency values and currency exchange rates will not be accurately predicted, which could significantly harm the fund's performance.

Performance

The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index.The fund's past performance (before and after taxes) is not necessarily an indication of future performance.

The fund can also experience short-term performance swings, as shown by the best and worst calendar quarter returns during the years depicted.

New Income Fund - Advisor Class

Calendar Year Returns

	Quarter Ended	Total Return
Best Quarter	6/30/09	5.02%
Worst Quarter	6/30/04	-2.41%

The fund's return for the six months ended 6/30/11 was 2.07%.

In addition, the average annual total returns table shows hypothetical after-tax returns to suggest how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or individual retirement account.

 Average Annual Total Returns

Periods ended

December 31, 2010

Average Annual Total Returns - Advisor Class T. Rowe Price New Income Fund, Inc.	1 Year	5 Years	Since inception	Inception Date
T. Rowe Price New Income Fund-Advisor Class	6.84%	5.95%	5.31%	Sep. 30, 2002
T. Rowe Price New Income Fund-Advisor Class Returns after taxes on distributions	5.30%	4.58%	3.93%	Sep. 30, 2002
T. Rowe Price New Income Fund-Advisor Class Returns after taxes on distributions and sale of fund shares	4.52%	4.41%	3.81%	Sep. 30, 2002
Barclays Capital U.S. Aggregate Bond Index	6.54%	5.80%	5.02%
Lipper Corporate Debt Funds A-Rated Average	7.51%	4.78%	4.63%

Updated performance information is available through troweprice.com or may be obtained by calling 1-800-638-8790. 

[1] T. Rowe Price Associates, Inc. is required to permanently waive a portion of its management fee charged to the fund in an amount sufficient to fully offset any acquired fund fees and expenses related to investments in other T. Rowe Price mutual funds. The amount of the waiver will vary each fiscal year in proportion to the amount invested in other T. Rowe Price mutual funds. The T. Rowe Price funds would be required to seek regulatory approval in order to terminate this arrangement.

[2] The figure shown under "Total annual fund operating expenses after fee waiver/expense reimbursement" does not match the "Ratio of expenses to average net assets" shown in the Financial Highlights table, as that figure does not include acquired fund fees and expenses.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price New Income Fund, Inc.

Prospectus Date

rr_ProspectusDate

Oct. 01, 2011

R Class | T. Rowe Price New Income Fund, Inc. | T. Rowe Price New Income Fund-R Class

Risk/Return:

rr_RiskReturnAbstract

Management fees

rr_ManagementFeesOverAssets

0.45%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.50%

^[1]

Other expenses

rr_OtherExpensesOverAssets

0.26%

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.03%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.24%

Fee waiver/expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

0.08%

^[1],[2]

Total annual fund operating expenses after fee waiver/expense reimbursement

rr_NetExpensesOverAssets

1.16%

^[2],[3]

1 year

rr_ExpenseExampleYear01

117

3 years

rr_ExpenseExampleYear03

378

5 years

rr_ExpenseExampleYear05

661

10 years

rr_ExpenseExampleYear10

1,469

Annual Return 2003

rr_AnnualReturn2003

5.19%

Annual Return 2004

rr_AnnualReturn2004

4.12%

Annual Return 2005

rr_AnnualReturn2005

2.36%

Annual Return 2006

rr_AnnualReturn2006

3.63%

Annual Return 2007

rr_AnnualReturn2007

5.79%

Annual Return 2008

rr_AnnualReturn2008

0.91%

Annual Return 2009

rr_AnnualReturn2009

11.80%

Annual Return 2010

rr_AnnualReturn2010

6.60%

Year to Date Return, Label

rr_YearToDateReturnLabel

The fund's return for the six months ended 6/30/11

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2011

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.00%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

4.95%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2004

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(2.57%)

1 Year

rr_AverageAnnualReturnYear01

6.60%

5 Years

rr_AverageAnnualReturnYear05

5.69%

Since inception

rr_AverageAnnualReturnSinceInception

5.05%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2002

R Class | T. Rowe Price New Income Fund, Inc. | T. Rowe Price New Income Fund-R Class | Returns after taxes on distributions

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

5.19%

5 Years

rr_AverageAnnualReturnYear05

4.39%

Since inception

rr_AverageAnnualReturnSinceInception

3.76%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2002

R Class | T. Rowe Price New Income Fund, Inc. | T. Rowe Price New Income Fund-R Class | Returns after taxes on distributions and sale of fund shares

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

4.36%

5 Years

rr_AverageAnnualReturnYear05

4.22%

Since inception

rr_AverageAnnualReturnSinceInception

3.64%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2002

R Class | T. Rowe Price New Income Fund, Inc.

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. Rowe Price

New Income Fund–R Class

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks the highest level of income consistent with the preservation of capital over time by investing primarily in marketable debt securities.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

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

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Fees and Expenses of the Fund's R Class

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

September 30, 2012

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 110.7% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

110.70%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

The figure shown under "Total annual fund operating expenses after free waiver/expense reimbursement" does not match the "Ratio of expenses to average net assets" shown in the Financial Highlights table, as that figure does not include acquired fund fees and expenses

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year, the fund's operating expenses remain the same, and the expense limitation currently in place is not renewed. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

In seeking income and capital preservation, the fund pursues a total return strategy. Active management of the portfolio can result in bonds being sold at gains or losses. However, over the long term, the fund seeks to achieve its objective by investing primarily in income-producing securities that possess what the fund believes are favorable total return (income plus changes in principal) characteristics.

The fund will invest at least 80% of its total assets in income-producing securities, which may include, but are not limited to, U.S. government and agency obligations, mortgage- and asset-backed securities, corporate bonds, foreign securities, collateralized mortgage obligations, Treasury inflation protected securities, and others, including, on occasion, equities.

Eighty percent (80%) of the debt securities purchased by the fund will be rated investment grade (AAA, AA, A, BBB, or an equivalent rating) by each of the major credit rating agencies (Standard & Poor's, Moody's, and Fitch) that have assigned a rating to the security or, if unrated, deemed to be of investment-grade quality by T. Rowe Price. Up to 15% of the fund's total assets may be invested in "split-rated securities," which are securities that have been rated investment grade by at least one rating agency but below investment grade by another rating agency. In addition, the fund may invest up to 5% of its total assets in securities that have received below investment-grade ratings from each of the rating agencies that have assigned ratings to the securities or, if unrated, deemed to be below investment-grade quality by T. Rowe Price.

The fund has considerable flexibility in seeking high yields. There are no maturity restrictions, so the fund can purchase longer-term bonds, which tend to have higher yields than shorter-term issues. However, the portfolio's weighted average maturity is expected to be between four and 15 years. In addition, when there is a large yield difference between the various quality levels, the fund may move down the credit scale and purchase lower-rated bonds with higher yields. When the difference is small or the outlook warrants, the fund may concentrate investments in higher-rated issues.

While most assets will typically be invested in bonds, the fund also invests in derivatives such as interest rate futures and forward currency exchange contracts inkeeping with the fund's objective s.

The fund may sell holdings for a variety of reasons, such as to adjust the portfolio's average maturity, duration, or credit quality or to shift assets into and out of higher-yielding or lower-yielding securities or different sectors.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund's share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management riskThe fund is subject to the risk that the investment adviser's judgments about the attractiveness, value, or potential appreciation of the fund's investments may prove to be incorrect. If the securities selected and strategies employed by the fund fail to produce the intended results, the fund could underperform other funds with similar objectives and investment strategies.

Interest rate risk  This is the risk that a rise in interest rates will cause the price of a fixed rate debt security to fall. Generally, the longer the maturity of a security or weighted average maturity of a fund, the greater the interest rate risk.

Credit risk  This is the risk that an issuer of a debt security or counterparty to an over-the-counter derivative could suffer an adverse change in financial condition that results in a payment default, security downgrade, or inability to meet a financial obligation.

Liquidity risk  This is the risk that the fund may not be able to sell a holdingin a timely manner at a desired price.

Foreign investing risk  This is the risk that the fund's investments in foreign securities may be adversely affected by political and economic conditions overseas, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

Prepayment risk and extension riskPrepayment risk is the risk that the principal on mortgage-backed securities, other asset-backed securities or any fixed income security with an embedded call option may be prepaid at any time, which could reduce yield and market value. The rate of prepayments tends to increase as interest rates fall, which could cause the average maturity of the portfolio to shorten. Extension risk may result from a rise in interest rates, which tends to make mortgage-backed securities, asset-backed securities, and other callable fixed income securities more volatile.

Derivatives risk  To the extent the fund uses interest rate futures and forward currency exchange contracts, it is exposed to additional volatility in comparison toinvesting directly in bonds and other debt securities.Derivatives can be illiquid and difficult to value , may involve leverage so that small changes produce disproportionate losses for the fund, and instruments not traded on an exchange are subject to the risk that a counterparty to the transaction will fail to meet its obligations under the derivatives contract. The fund's principal use of derivatives involves the risk that anticipated interest rate movements and changes in currency values and currency exchange rates will not be accurately predicted, which could significantly harm the fund's performance.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund's share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index.The fund's past performance (before and after taxes) is not necessarily an indication of future performance.

The fund can also experience short-term performance swings, as shown by the best and worst calendar quarter returns during the years depicted.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

1-800-638-8790

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

troweprice.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund's past performance (before and after taxes) is not necessarily an indication of future performance.

Bar Chart [Heading]

rr_BarChartHeading

New Income Fund - R Class

Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return
Best Quarter	6/30/09	4.95%
Worst Quarter	6/30/04	-2.57%

The fund's return for the six months ended 6/30/11 was 2.00%.

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns

Periods ended

December 31, 2010

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or individual retirement account.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

In addition, the average annual total returns table shows hypothetical after-tax returns to suggest how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or individual retirement account.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com or may be obtained by calling 1-800-638-8790. 

R Class | T. Rowe Price New Income Fund, Inc. | Barclays Capital U.S. Aggregate Bond Index

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

6.54%

5 Years

rr_AverageAnnualReturnYear05

5.80%

Since inception

rr_AverageAnnualReturnSinceInception

5.02%

R Class | T. Rowe Price New Income Fund, Inc. | Lipper Corporate Debt Funds A-Rated Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

7.51%

5 Years

rr_AverageAnnualReturnYear05

4.78%

Since inception

rr_AverageAnnualReturnSinceInception

4.63%

[1] T. Rowe Price Associates, Inc. is required to permanently waive a portion of its management fee charged to the fund in an amount sufficient to fully offset any acquired fund fees and expenses related to investments in other T. Rowe Price mutual funds. The amount of the waiver will vary each fiscal year in proportion to the amount invested in other T. Rowe Price mutual funds. The T. Rowe Price funds would be required to seek regulatory approval in order to terminate this arrangement.

[2] T. Rowe Price Associates, Inc. has agreed (through September 30, 2012) to waive its fees and/or bear any expenses (excluding interest, taxes, brokerage, extraordinary expenses, and acquired fund fees) that would cause the class's ratio of expenses to average net assets to exceed 1.15%. Termination of the agreement would require approval by the fund's Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 1.15%) are subject to reimbursement to T. Rowe Price Associates, Inc. by the fund whenever the class's expense ratio is below 1.15%. However, no reimbursement will be made more than three years after the waiver or payment, or if it would result in the expense ratio exceeding 1.15%.

[3] The figure shown under "Total annual fund operating expenses after free waiver/expense reimbursement" does not match the "Ratio of expenses to average net assets" shown in the Financial Highlights table, as that figure does not include acquired fund fees and expenses.

XML

R Class | T. Rowe Price New Income Fund, Inc.

T. Rowe Price

New Income Fund–R Class

Investment Objective

The fund seeks the highest level of income consistent with the preservation of capital over time by investing primarily in marketable debt securities.

Fees and Expenses

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

Fees and Expenses of the Fund's R Class

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Annual Fund Operating Expenses -		R Class T. Rowe Price New Income Fund, Inc. T. Rowe Price New Income Fund-R Class
Management fees		0.45%
Distribution and service (12b-1) fees	[1]	0.50%
Other expenses		0.26%
Acquired fund fees and expenses		0.03%
Total annual fund operating expenses		1.24%
Fee waiver/expense reimbursement	[1][2]	0.08%
Total annual fund operating expenses after fee waiver/expense reimbursement	[2][3]	1.16%

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year, the fund's operating expenses remain the same, and the expense limitation currently in place is not renewed. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - (USD $)	1 year	3 years	5 years	10 years
R Class T. Rowe Price New Income Fund, Inc. T. Rowe Price New Income Fund-R Class	117	378	661	1,469

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 110.7% of the average value of its portfolio.

Investments, Risks, and Performance

Principal Investment Strategies

In seeking income and capital preservation, the fund pursues a total return strategy. Active management of the portfolio can result in bonds being sold at gains or losses. However, over the long term, the fund seeks to achieve its objective by investing primarily in income-producing securities that possess what the fund believes are favorable total return (income plus changes in principal) characteristics.

The fund will invest at least 80% of its total assets in income-producing securities, which may include, but are not limited to, U.S. government and agency obligations, mortgage- and asset-backed securities, corporate bonds, foreign securities, collateralized mortgage obligations, Treasury inflation protected securities, and others, including, on occasion, equities.

Eighty percent (80%) of the debt securities purchased by the fund will be rated investment grade (AAA, AA, A, BBB, or an equivalent rating) by each of the major credit rating agencies (Standard & Poor's, Moody's, and Fitch) that have assigned a rating to the security or, if unrated, deemed to be of investment-grade quality by T. Rowe Price. Up to 15% of the fund's total assets may be invested in "split-rated securities," which are securities that have been rated investment grade by at least one rating agency but below investment grade by another rating agency. In addition, the fund may invest up to 5% of its total assets in securities that have received below investment-grade ratings from each of the rating agencies that have assigned ratings to the securities or, if unrated, deemed to be below investment-grade quality by T. Rowe Price.

The fund has considerable flexibility in seeking high yields. There are no maturity restrictions, so the fund can purchase longer-term bonds, which tend to have higher yields than shorter-term issues. However, the portfolio's weighted average maturity is expected to be between four and 15 years. In addition, when there is a large yield difference between the various quality levels, the fund may move down the credit scale and purchase lower-rated bonds with higher yields. When the difference is small or the outlook warrants, the fund may concentrate investments in higher-rated issues.

While most assets will typically be invested in bonds, the fund also invests in derivatives such as interest rate futures and forward currency exchange contracts inkeeping with the fund's objective s.

The fund may sell holdings for a variety of reasons, such as to adjust the portfolio's average maturity, duration, or credit quality or to shift assets into and out of higher-yielding or lower-yielding securities or different sectors.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund's share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management riskThe fund is subject to the risk that the investment adviser's judgments about the attractiveness, value, or potential appreciation of the fund's investments may prove to be incorrect. If the securities selected and strategies employed by the fund fail to produce the intended results, the fund could underperform other funds with similar objectives and investment strategies.

Interest rate risk  This is the risk that a rise in interest rates will cause the price of a fixed rate debt security to fall. Generally, the longer the maturity of a security or weighted average maturity of a fund, the greater the interest rate risk.

Credit risk  This is the risk that an issuer of a debt security or counterparty to an over-the-counter derivative could suffer an adverse change in financial condition that results in a payment default, security downgrade, or inability to meet a financial obligation.

Liquidity risk  This is the risk that the fund may not be able to sell a holdingin a timely manner at a desired price.

Foreign investing risk  This is the risk that the fund's investments in foreign securities may be adversely affected by political and economic conditions overseas, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

Prepayment risk and extension riskPrepayment risk is the risk that the principal on mortgage-backed securities, other asset-backed securities or any fixed income security with an embedded call option may be prepaid at any time, which could reduce yield and market value. The rate of prepayments tends to increase as interest rates fall, which could cause the average maturity of the portfolio to shorten. Extension risk may result from a rise in interest rates, which tends to make mortgage-backed securities, asset-backed securities, and other callable fixed income securities more volatile.

Derivatives risk  To the extent the fund uses interest rate futures and forward currency exchange contracts, it is exposed to additional volatility in comparison toinvesting directly in bonds and other debt securities.Derivatives can be illiquid and difficult to value , may involve leverage so that small changes produce disproportionate losses for the fund, and instruments not traded on an exchange are subject to the risk that a counterparty to the transaction will fail to meet its obligations under the derivatives contract. The fund's principal use of derivatives involves the risk that anticipated interest rate movements and changes in currency values and currency exchange rates will not be accurately predicted, which could significantly harm the fund's performance.

Performance

The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index.The fund's past performance (before and after taxes) is not necessarily an indication of future performance.

The fund can also experience short-term performance swings, as shown by the best and worst calendar quarter returns during the years depicted.

New Income Fund - R Class

Calendar Year Returns

	Quarter Ended	Total Return
Best Quarter	6/30/09	4.95%
Worst Quarter	6/30/04	-2.57%

The fund's return for the six months ended 6/30/11 was 2.00%.

In addition, the average annual total returns table shows hypothetical after-tax returns to suggest how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or individual retirement account.

Average Annual Total Returns

Periods ended

December 31, 2010

Average Annual Total Returns - R Class T. Rowe Price New Income Fund, Inc.	1 Year	5 Years	Since inception	Inception Date
T. Rowe Price New Income Fund-R Class	6.60%	5.69%	5.05%	Sep. 30, 2002
T. Rowe Price New Income Fund-R Class Returns after taxes on distributions	5.19%	4.39%	3.76%	Sep. 30, 2002
T. Rowe Price New Income Fund-R Class Returns after taxes on distributions and sale of fund shares	4.36%	4.22%	3.64%	Sep. 30, 2002
Barclays Capital U.S. Aggregate Bond Index	6.54%	5.80%	5.02%
Lipper Corporate Debt Funds A-Rated Average	7.51%	4.78%	4.63%

Updated performance information is available through troweprice.com or may be obtained by calling 1-800-638-8790. 

[1] T. Rowe Price Associates, Inc. is required to permanently waive a portion of its management fee charged to the fund in an amount sufficient to fully offset any acquired fund fees and expenses related to investments in other T. Rowe Price mutual funds. The amount of the waiver will vary each fiscal year in proportion to the amount invested in other T. Rowe Price mutual funds. The T. Rowe Price funds would be required to seek regulatory approval in order to terminate this arrangement.

[2] T. Rowe Price Associates, Inc. has agreed (through September 30, 2012) to waive its fees and/or bear any expenses (excluding interest, taxes, brokerage, extraordinary expenses, and acquired fund fees) that would cause the class's ratio of expenses to average net assets to exceed 1.15%. Termination of the agreement would require approval by the fund's Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 1.15%) are subject to reimbursement to T. Rowe Price Associates, Inc. by the fund whenever the class's expense ratio is below 1.15%. However, no reimbursement will be made more than three years after the waiver or payment, or if it would result in the expense ratio exceeding 1.15%.

[3] The figure shown under "Total annual fund operating expenses after free waiver/expense reimbursement" does not match the "Ratio of expenses to average net assets" shown in the Financial Highlights table, as that figure does not include acquired fund fees and expenses.

XML

Investor Class | T. Rowe Price New Income Fund, Inc.

T. Rowe Price

New Income Fund

Investment Objective

The fund seeks the highest level of income consistent with the preservation of capital over time by investing primarily in marketable debt securities.

Fees and Expenses

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

Fees and Expenses of the Fund

Shareholder fees (fees paid directly from your investment)

Shareholder Fees - (USD $)		Investor Class T. Rowe Price New Income Fund, Inc.
Maximum sales charge (load) imposed on purchases		none
Maximum deferred sales charge (load)		none
Redemption fee		none
Maximum account fee	[1]	20

 Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Annual Fund Operating Expenses -		Investor Class T. Rowe Price New Income Fund, Inc.
Management fees		0.45%
Distribution and service (12b-1) fees		none
Other expenses		0.18%
Acquired fund fees and expenses		0.03%
Total annual fund operating expenses		0.66%
Fee waiver/expense reimbursement	[1]	0.02%
Total annual fund operating expenses after fee waiver/expense reimbursement	[2]	0.64%

Example

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

Expense Example - (USD $)	1 year	3 years	5 years	10 years
Investor Class T. Rowe Price New Income Fund, Inc.	65	205	357	798

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 110.7% of the average value of its portfolio.

Investments, Risks, and Performance

Principal Investment Strategies

In seeking income and capital preservation, the fund pursues a total return strategy. Active management of the portfolio can result in bonds being sold at gains or losses. However, over the long term, the fund seeks to achieve its objective by investing primarily in income-producing securities that possess what the fund believes are favorable total return (income plus changes in principal) characteristics.

The fund will invest at least 80% of its total assets in income-producing securities, which may include, but are not limited to, U.S. government and agency obligations, mortgage- and asset-backed securities, corporate bonds, foreign securities, collateralized mortgage obligations, Treasury inflation protected securities, and others, including, on occasion, equities.

Eighty percent (80%) of the debt securities purchased by the fund will be rated investment grade (AAA, AA, A, BBB, or an equivalent rating) by each of the major credit rating agencies (Standard & Poor's, Moody's, and Fitch) that have assigned a rating to the security or, if unrated, deemed to be of investment-grade quality by T. Rowe Price. Up to 15% of the fund's total assets may be invested in "split-rated securities," which are securities that have been rated investment grade by at least one rating agency but below investment grade by another rating agency. In addition, the fund may invest up to 5% of its total assets in securities that have received below investment-grade ratings from each of the rating agencies that have assigned ratings to the securities or, if unrated, deemed to be below investment-grade quality by T. Rowe Price.

The fund has considerable flexibility in seeking high yields. There are no maturity restrictions, so the fund can purchase longer-term bonds, which tend to have higher yields than shorter-term issues. However, the portfolio's weighted average maturity is expected to be between four and 15 years. In addition, when there is a large yield difference between the various quality levels, the fund may move down the credit scale and purchase lower-rated bonds with higher yields. When the difference is small or the outlook warrants, the fund may concentrate investments in higher-rated issues.

While most assets will typically be invested in bonds, the fund also invests in derivatives such as interest rate futures and forward currency exchange contracts inkeeping with the fund's objective .

The fund may sell holdings for a variety of reasons, such as to adjust the portfolio's average maturity, duration, or credit quality or to shift assets into and out of higher-yielding or lower-yielding securities or different sectors.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund's share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management riskThe fund is subject to the risk that the investment adviser's judgments about the attractiveness, value, or potential appreciation of the fund's investments may prove to be incorrect. If the securities selected and strategies employed by the fund fail to produce the intended results, the fund could underperform other funds with similar objectives and investment strategies.

Interest rate risk  This is the risk that a rise in interest rates will cause the price of a fixed rate debt security to fall. Generally, the longer the maturity of a security or weighted average maturity of a fund, the greater the interest rate risk.

Credit risk  This is the risk that an issuer of a debt security or counterparty to an over-the-counter derivative could suffer an adverse change in financial condition that results in a payment default, security downgrade, or inability to meet a financial obligation.

Liquidity risk  This is the risk that the fund may not be able to sell a holdingin a timely manner at a desired price.

Foreign investing risk  This is the risk that the fund's investments in foreign securities may be adversely affected by political and economic conditions overseas, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

Prepayment risk and extension riskPrepayment risk is the risk that the principal on mortgage-backed securities, other asset-backed securities or any fixed income security with an embedded call option may be prepaid at any time, which could reduce yield and market value. The rate of prepayments tends to increase as interest rates fall, which could cause the average maturity of the portfolio to shorten. Extension risk may result from a rise in interest rates, which tends to make mortgage-backed securities, asset-backed securities, and other callable fixed income securities more volatile.

Derivatives risk  To the extent the fund uses interest rate futures and forward currency exchange contracts, it is exposed to additional volatility in comparison toinvesting directly in bonds and other debt securities.Derivatives can be illiquid and difficult to value , may involve leverage so that small changes produce disproportionate losses for the fund, and instruments not traded on an exchange are subject to the risk that a counterparty to the transaction will fail to meet its obligations under the derivatives contract. The fund's principal use of derivatives involves the risk that anticipated interest rate movements and changes in currency values and currency exchange rates will not be accurately predicted, which could significantly harm the fund's performance.

Performance

The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index. The fund's past performance (before and after taxes) is not necessarily an indication of future performance.

The fund can also experience short-term performance swings, as shown by the best and worst calendar quarter returns during the years depicted.

New Income Fund

Calendar Year Returns

	Quarter Ended	Total Return
Best Quarter	6/30/09	5.07%
Worst Quarter	6/30/04	-2.36%

The fund's return for the six months ended 6/30/11 was 2.27%.

In addition, the average annual total returns table shows hypothetical after-tax returns to suggest how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or individual retirement account.

Average Annual Total Returns

Periods ended

December 31, 2010

Average Annual Total Returns - Investor Class	1 Year	5 Years	10 Years
T. Rowe Price New Income Fund, Inc.	7.16%	6.21%	5.97%
T. Rowe Price New Income Fund, Inc. Returns after taxes on distributions	5.55%	4.77%	4.38%
T. Rowe Price New Income Fund, Inc. Returns after taxes on distributions and sale of fund shares	4.73%	4.60%	4.23%
T. Rowe Price New Income Fund, Inc. Barclays Capital U.S. Aggregate Bond Index	6.54%	5.80%	5.84%
T. Rowe Price New Income Fund, Inc. Lipper Corporate Debt Funds A-Rated Average	7.51%	4.78%	5.24%

Updated performance information is available through troweprice.com or may be obtained by calling 1-800-225-5132. 

[1] Subject to certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee.

[1] T. Rowe Price Associates, Inc. is required to permanently waive a portion of its management fee charged to the fund in an amount sufficient to fully offset any acquired fund fees and expenses related to investments in other T. Rowe Price mutual funds. The amount of the waiver will vary each fiscal year in proportion to the amount invested in other T. Rowe Price mutual funds. The T. Rowe Price funds would be required to seek regulatory approval in order to terminate this arrangement.

[2] The figure shown under "Total annual fund operating expenses after fee waiver/expense reimbursement" does not match the "Ratio of expenses to average net assets" shown in the Financial Highlights table, as that figure does not include acquired fund fees and expenses.