UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 11-K

(Mark One)

ý ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2011

OR

¨ TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from  to 

Commission file number 0-27058

PAREXEL International Corporation 401(k) Retirement Savings Plan

(Full Title of the Plan)

PAREXEL International Corporation

195 West Street

Waltham, MA 02451

(Name of Issuer of the Securities Held Pursuant to the

Plan and the Address of its Principal Executive Offices)

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Audited Financial Statements and Supplemental Schedule

Year Ended December 31, 2011

Contents

Report of Independent Registered Public Accounting Firm	1
Audited Financial Statements
Statements of Net Assets Available for Benefits	2
Statement of Changes in Net Assets Available for Benefits	3
Notes to Financial Statements	4
Supplemental Schedule
Schedule H, Line 4i – Schedule of Assets (Held at End of Year)	9

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Report of Independent Registered Public Accounting Firm

The Plan Administrator and Participants

PAREXEL International Corporation 401(k) Retirement Savings Plan

We have audited the accompanying statements of net assets available for benefits of PAREXEL International Corporation 401(k) Retirement Savings Plan as of December 31, 2011 and December 31, 2010, and the related statement of changes in net assets available for benefits for the year ended December 31, 2011. These financial statements are the responsibility of the Plan’s management. Our responsibility is to express an opinion on these financial statements based on our audits.

We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. We were not engaged to perform an audit of the Plan’s internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Plan’s internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in all material respects, the net assets available for benefits of the Plan at December 31, 2011 and December 31, 2010, and the changes in its net assets available for benefits for the year ended December 31, 2011, in conformity with U.S. generally accepted accounting principles.

Our audits were conducted for the purpose of forming an opinion on the financial statements taken as a whole. The accompanying supplemental schedule of assets (held at end of year) as of December 31, 2011 is presented for purposes of additional analysis and is not a required part of the financial statements but is supplementary information required by the Department of Labor’s Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974. Such information is the responsibility of the Plan’s management. The information has been subjected to the auditing procedures applied in our audits of the financial statements and, in our opinion, is fairly stated in all material respects in relation to the financial statements taken as a whole.

/s/ Ernst & Young LLP

Boston, Massachusetts

June 19, 2012

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PAREXEL International Corporation 401(k) Retirement Savings Plan

Statement of Net Assets Available for Benefits

	December 31, 2011		December 31, 2010
Assets
Investments, at fair value:	$	145,120,781	$	137,647,032
Receivables:
Notes receivable from participants	2,157,117		1,802,378
Participants’ contributions	491,080		410,308
Employer contributions	151,176		122,217
Total receivables	2,799,373		2,334,903
Net assets available for benefits	$	147,920,154	$	139,981,935

See accompanying notes.

2

PAREXEL International Corporation 401(k) Retirement Savings Plan

Statement of Changes in Net Assets Available for Benefits

	Year Ended
	December 31, 2011
Additions
Contributions:
Participants	$	16,443,241
Employer	4,652,875
Rollovers	2,345,198
Total contributions	23,441,314
Interest income on notes receivable from participants	89,661
Investment income (loss):
Dividends and interest income	3,283,854
Net depreciation in fair value of investments	(8,352,140		)
Net investment loss	(5,068,286		)
Total additions	18,462,689
Deductions
Benefit payments	10,494,787
Administrative expenses	29,683
Total deductions	10,524,470
Net increase	7,938,219
Net assets available for benefits at beginning of year	139,981,935
Net assets available for benefits at end of year	$	147,920,154

See accompanying notes.

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PAREXEL International Corporation 401(k) Retirement Savings Plan

Notes to Financial Statements

December 31, 2011

1. Description of the Plan

The following description of the PAREXEL International Corporation (the Company or Plan Sponsor) 401(k) Retirement Savings Plan (the Plan) provides only general information. Participants should refer to the Plan Document for a more complete description of the Plan’s provisions.

General

The Plan is a defined contribution 401(k) profit sharing plan established effective January 1, 1988. It is subject to the provisions of the Internal Revenue Code of 1986 (the Code), as amended, and the Employee Retirement Income Security Act of 1974 (ERISA).

The Plan covers all full-time, part-time, and temporary employees of the Company who are age 21 years or older.

Contributions

Participants may contribute up to 60% of their annual compensation, as defined and including 100% of cash bonuses, subject to Internal Revenue Service (IRS) limitations. Participants may also contribute amounts representing distributions from other qualified defined benefit or defined contribution plans.

The Company matches an amount equal to 100% of the first 3% of compensation contributed by each participant, not to exceed $3,000 per participant per annum. In addition, the Company may make a discretionary contribution to be allocated to eligible participants in the ratio that each eligible participant’s compensation bears to the total compensation paid to all eligible participants for the Plan year. During the Plan year ended December 31, 2011, no discretionary contribution was made to the Plan by the Company.

The Plan includes the automatic enrollment of contributions whereby an eligible employee’s compensation would be reduced and automatic enrollment contributions made on his/her behalf unless an affirmative election not to do so was made.

Participant Accounts

Participant accounts are maintained by an independent record keeper, Fidelity Retirement Investment Services. Each participant’s account is credited with the participant’s contributions, Company matching contributions, an allocation of Plan earnings (losses) based upon investment elections, and is charged with an allocation of administrative expenses, as applicable. The benefit to which a participant is entitled is the benefit that can be provided from the participant’s account.

Vesting

Participants are immediately vested in their voluntary contributions, plus actual earnings thereon. Vesting in Company contributions and earnings thereon is based on years of continuous service. Each participant vests in 20% increments for each of the first five years of credited service, as defined.

Forfeitures

Forfeitures of terminated participants’ non-vested accounts can be used to reduce future Company contributions to the Plan, and pay for the Plan’s administrative expenses. During the year ended December 31, 2011, forfeitures used to offset Company contributions amounted to $718,120, and $4,025 was used to pay administrative expenses. At December 31, 2011 and December 31, 2010, forfeited non-vested amounts available to offset future Company contributions amounted to $167,937 and $189,853, respectively.

Notes Receivable from Participants

A participant may borrow from his or her account a minimum of $1,000, not to exceed the lesser of $50,000 or 50% of his or her vested account balance. Loans are secured by the balance in the participant’s account and bear interest at a rate commensurate with local market rates for similar loans. Loans must be repaid within five years, unless the loan is for the purchase of a primary residence, in which case it is repayable in ten years. Principal and interest are paid ratably through payroll deductions.

Benefits

A participant’s account is payable in a lump-sum amount equal to the vested value of his or her account upon termination of service, retirement or early retirement, if elected, death, permanent or total disability, or age 59 1/2. In-service withdrawals may

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be made in the event of a financial hardship, as defined by the Plan, but will result in the suspension of all contributions for six months. Hardship withdrawals are strictly regulated by the Internal Revenue Service (IRS) and a participant must exhaust all available loan options and available distributions prior to requesting a hardship withdrawal.

Plan Termination

Although it has not expressed any intent to do so, the Company has the right under the Plan to discontinue its contributions at any time and to terminate the Plan subject to the provisions of ERISA. In the event of a Plan termination, participants will become 100% vested in their accounts.

2. Summary of Significant Accounting Policies

Basis of Accounting

The financial statements have been prepared on the accrual basis of accounting.

Investment Valuation and Income Recognition

Investments held by the Plan are stated at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). Investments in mutual funds are valued at quoted market prices, which represent the net asset value of shares held by the Plan at year end. The Company stock is valued based upon quoted market prices.

Security transactions are accounted for on a trade-date basis, and realized gains and losses on investments are calculated as the difference between the cost of the investment shares sold and the market value of the shares sold. The net depreciation in the fair value of investments reported in the statement of changes in net assets available for benefits includes realized and unrealized gains and losses on investments. Investment income is recorded on the accrual basis. Dividends are recorded as of the ex-dividend date.

Notes Receivable from Participants

Notes receivable from participants represent participant loans that are recorded at their unpaid principal balance plus any accrued but unpaid interest. Interest income on notes receivable from participants is recorded when it is earned. Related fees are recorded as administrative expenses and are expensed when they are incurred. No allowance for credit losses has been recorded as of December 31, 2011 or 2010. If a participant ceases to make loan repayments and the plan administrator deems the participant loan to be a distribution, the participant loan balance is reduced and a benefit payment is recorded.

Use of Estimates

The preparation of financial statements in conformity with accepted accounting principles generally accepted in the United States requires management to make estimates that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

Expenses

All Plan expenses are paid by the Company, except those relating to record keeping fees on participant loans, which are allocated to the individual participants’ accounts.

New Accounting Pronouncements

In May 2011, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2011-04, Amendments to Achieve Common Fair Value Measurements and Disclosure Requirements in U.S. GAAP and IFRSs, (ASU 2011-04). ASU 2011-04 amended Accounting Standards Codification (ASC) 820, Fair Value Measurements and Disclosures, to converge the fair value measurement guidance in GAAP and International Financial Reporting Standards (IFRSs). Some of the amendments clarify the application of existing fair value measurement requirements, while other amendments change a particular principle in ASC 820. In addition, ASU 2011-04 requires additional fair value disclosures. The amendments are to be applied prospectively and are effective for annual periods beginning after December 15, 2011. Plan management is currently evaluating the effect that the provisions of ASU 2011-04 will have on the Plan’s financial statements.

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3. Investments

The Plan’s investments (including investments bought, sold, and held during the year) depreciated in value as follows:

	Year Ended
	December 31, 2011
Mutual funds	$	(8,300,118	)
PAREXEL International Corporation Common Stock	(52,022		)
Net depreciation in fair value of investments	$	(8,352,140	)

The following table lists the investments that accounted for greater than 5% of the net assets available for benefits:

	December 31, 2011		December 31, 2010
Fidelity Contrafund K	$	26,056,426	$	26,453,216
Fidelity Diversified International Fund	$	11,855,942	$	14,160,401
Fidelity Magellan Fund	$	9,623,688	$	10,877,899
Fidelity Retirement Money Market Portfolio	$	8,071,584	$	6,794,342
Fidelity Intermediate Bond Fund	*		$	6,638,621
Fidelity Fund	*		$	6,601,351
* Investment less than 5% of net assets

4. Fair Value Measurements

The Plan applies the provisions of ASC 820, Fair Value Measurements and Disclosures. ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The Plan establishes a three level hierarchy to prioritize the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are described below:

• Level 1 – Unadjusted quoted prices in active markets that are accessible to the reporting entity at the measurement date for identical assets and liabilities.

• Level 2 – Inputs other than quoted prices in active markets for identical assets and liabilities that are observable either directly or indirectly for substantially the full term of the asset or liability. Level 2 inputs include the following:

◦ quoted prices for similar assets and liabilities in active markets

◦ quoted prices for identical or similar assets or liabilities in markets that are not active

◦ observable inputs other than quoted prices that are used in the valuation of the asset or liabilities (e.g., interest rate and yield curve quotes at commonly quoted intervals)

◦ inputs that are derived principally from or corroborated by observable market data by correlation or other means

• Level 3 – Unobservable inputs for the assets or liability (i.e., supported by little or no market activity). Level 3 inputs include management’s own assumption about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk).

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The following table sets forth by level, within the fair value hierarchy, the Plan’s investments carried at fair value as of December 31, 2011:

	Level 1		Level 2		Level 3		Total
Mutual Funds
Stock Funds	$	116,479,719	$	—	$	—	$	116,479,719
Bond Funds	12,163,937		—		—		12,163,937
Short Term	8,072,326		—		—		8,072,326
Blended Funds	6,014,293		—		—		6,014,293
Total Mutual Funds	$	142,730,275	$	—	$	—	$	142,730,275
PAREXEL International Corporation Common Stock	2,390,506		—		—		2,390,506
Total	$	145,120,781	$	—	$	—	$	145,120,781

The following table sets forth by level, within the fair value hierarchy, the Plan’s investments carried at fair value as of December 31, 2010:

	Level 1		Level 2		Level 3		Total
Mutual Funds
Stock Funds	$	111,991,528	$	—	$	—	$	111,991,528
Bond Funds	10,763,270		—		—		10,763,270
Short Term	6,795,131		—		—		6,795,131
Blended Funds	5,737,723		—		—		5,737,723
Total Mutual Funds	$	135,287,652	$	—	$	—	$	135,287,652
PAREXEL International Corporation Common Stock	2,359,380		—		—		2,359,380
Total	$	137,647,032	$	—	$	—	$	137,647,032

Mutual funds are valued at the net asset value of shares held by the Plan based on quoted prices in the active market; PAREXEL International Corporation Common Stock is valued at the closing market price on the Nasdaq on December 31, 2011 and December 31, 2010, respectively. During the twelve months ended December 31, 2011 and December 31, 2010, there were no transfers between Level 1, Level 2, or Level 3, respectively.

5. Transactions and Agreements with Parties-in-Interest

The Plan holds shares of mutual funds managed by Fidelity, the trustee of the Plan. The Plan also holds shares of the common stock of the Company. These holdings qualify as party-in-interest transactions; however, they are exempt from the prohibited transactions rules under ERISA. The Plan received no common stock dividends from the Company for 2011.

6. Risks and Uncertainties

The Plan and its participants invest in various investment securities. Investment securities are exposed to various risks such as interest rate, market, liquidity and credit risks. Due to the level of risk associated with certain investment securities, it is at least reasonably possible that changes in the values of investment securities will occur in the near term, and that such changes could materially affect participants’ account balances and the amounts reported in the statements of net assets available for benefits.

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7. Income Tax Status

The underlying non-standardized prototype plan has received an opinion letter from the Internal Revenue Service (IRS) dated March 31, 2008 stating that the form of the plan is qualified under Section 401(a) of the Internal Revenue Code (the Code) and, therefore, the related trust is tax-exempt. In accordance with Revenue Procedures 2011-6 and 2011-49, the plan administrator has determined that it is eligible to and has chosen to rely on the current IRS prototype plan opinion letter. Once qualified, the Plan is required to operate in conformity with the Code to maintain its qualified status. The plan administrator has indicated that it will take the necessary steps, if any, to bring the Plan's operations into compliance with the Code.

Accounting principles generally accepted in the United States require plan management to evaluate uncertain tax positions taken by the Plan. The financial statement effects of a tax position are recognized when the position is more likely than not, based on the technical merits, to be sustained upon examination by the IRS. The plan administrator has analyzed the tax positions taken by the Plan, and has concluded that as of December 31, 2011, there are no uncertain positions taken or expected to be taken. The Plan has recognized no interest or penalties related to uncertain tax positions. The Plan is subject to routine audits by taxing jurisdictions; however, there are currently no audits for any tax periods in progress. The plan administrator believes it is no longer subject to income tax examinations for years prior to 2008.

8. Reconciliation of Financial Statements to Form 5500

The following is a reconciliation of the net assets available for plan benefits per the financial statements to the Form 5500 as of December 31, 2011 and December 31, 2010:

	December 31, 2011		December 31, 2010
Net assets available for plan benefits per financial statements	$	147,920,154	$	139,981,935
Less: participants’ contributions receivable	491,080		410,308
Less: employer contributions receivable	151,176		122,217
Net assets available for plan benefits per Form 5500	$	147,277,898	$	139,449,410

The following is a reconciliation of the changes in net assets available for plan benefits per the financial statements to the Form 5500 as of December 31, 2011:

	December 31, 2011
Net increase per financial statements	$	7,938,219
Less: participants' contributions receivable in 2011	491,080
Less: employer contributions receivable in 2011	151,176
Add: participants' contributions receivable in 2010	410,308
Add: employer contributions receivable in 2010	122,217
Net income per Form 5500	$	7,828,488

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Supplemental Schedule

PAREXEL International Corporation 401(k) Retirement Savings Plan

Schedule H, Line 4i – Schedule of Assets (Held at End of Year)

EIN No. 04-2776269 Plan No. 001

December 31, 2011

Identity of Issuer, Borrower, Lessor, or Similar Party	Description of Investment, Including Maturity Date, Rate of Interest, Collateral, Par, or Maturity Value	Current Value
Mutual Funds:
Fidelity Contrafund K*	386,537 shares	$	26,056,426
Fidelity Diversified International Fund*	465,304 shares	11,855,942
Fidelity Magellan Fund*	152,805 shares	9,623,688
Fidelity Retirement Money Market Portfolio*	8,071,584 shares	8,071,584
Fidelity Intermediate Bond Fund*	648,579 shares	7,056,540
Fidelity Fund*	203,004 shares	6,323,575
Fidelity Freedom K 2035*	553,802 shares	6,939,140
Fidelity Freedom K 2030*	546,471 shares	6,852,750
Fidelity Freedom K 2040*	528,240 shares	6,639,983
Artisan Mid Cap Fund	198,167 shares	6,525,642
Fidelity Balanced Fund*	330,637 shares	6,014,293
Fidelity Freedom K 2020*	478,426 shares	5,946,831
Fidelity Freedom K 2025*	392,730 shares	4,885,565
Fidelity Small Cap Stock Fund*	252,898 shares	4,182,935
Fidelity Freedom K 2045*	314,774 shares	3,985,043
Fidelity Low-Priced Stock Fund*	91,548 shares	3,268,262
PIM Total RT Inst	280,267 shares	3,046,499
Fidelity Freedom K 2015*	216,431 shares	2,625,302
Oakmark Fund	51,894 shares	2,163,446
Fidelity Freedom K 2050*	166,479 shares	2,105,959
Spartan US Bond Index*	174,949 shares	2,060,898
Spartan 500 Index*	34,056 shares	1,515,172
Fidelity Freedom K 2010*	91,647 shares	1,108,933
Spartan International Index*	30,654 shares	911,957
Spartan Extended Market Index*	23,551 shares	835,110
Fidelity Freedom K Income*	68,107 shares	769,604
Fidelity Freedom K 2000*	47,146 shares	538,878
ALLNZ NFJ Div Val I	41,316 shares	473,072
Fidelity Freedom K 2005*	28,923 shares	346,504
Fidelity Cash Reserve Fund*	742 shares	742
PAREXEL International Corporation Common Stock*	115,261 shares	2,390,506
Participant Loans*	4% to 10%	2,157,117
TOTAL ASSETS		$	147,277,898

*Indicates party-in-interest to the Plan.

Note: Cost information has not been included because all investments are participant directed.

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Signatures

Pursuant to the requirements of the Securities and Exchange Act of 1934, the PAREXEL International Corporation 401(k) Retirement Savings Plan has duly caused this annual report to be signed on its behalf by the undersigned hereto duly authorized.

Date:	June 19, 2012	PAREXEL International Corporation 401(k) Retirement Savings Plan
		By:	/s/ Todd Cowgill
			Todd Cowgill
			Vice President, Compensation Benefits & HRIS

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Index to Exhibits

Exhibit No.
23	Consent of Independent Registered Public Accounting Firm

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Exhibit 23

Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the Registration Statement (Form S-8 No. 333-109317) pertaining to the PAREXEL International Corporation 401(k) Retirement Savings Plan of PAREXEL International Corporation of our report dated June 19, 2012, with respect to the financial statements and schedule of the PAREXEL International Corporation 401(k) Retirement Savings Plan included in this Annual Report (Form 11-K) for the year ended December 31, 2011.

/s/ Ernst & Young LLP

Boston, Massachusetts

June 19, 2012

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