-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 VwZlNT8C33EpLx7TvxyfHB/bldn+HNPgbWsoDvBdB4rC4/B+7/YeZXOywQC7wcms
 dXmHQPGUM1j5rs9dmPW+YQ==

<SEC-DOCUMENT>0000799729-07-000010.txt : 20070907
<SEC-HEADER>0000799729-07-000010.hdr.sgml : 20070907
<ACCEPTANCE-DATETIME>20070907111108
ACCESSION NUMBER:		0000799729-07-000010
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070906
FILED AS OF DATE:		20070907
DATE AS OF CHANGE:		20070907

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PAREXEL INTERNATIONAL CORP
		CENTRAL INDEX KEY:			0000799729
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMMERCIAL PHYSICAL & BIOLOGICAL RESEARCH [8731]
		IRS NUMBER:				042776269
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		195 WEST ST
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
		BUSINESS PHONE:		7814879900

	MAIL ADDRESS:	
		STREET 1:		195 WEST ST
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CALLOW A DANA JR
		CENTRAL INDEX KEY:			0001018241

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-21244
		FILM NUMBER:		071104653

	BUSINESS ADDRESS:	
		STREET 1:		BOSTON MILLENNIA PARTNERS
		STREET 2:		30 ROWES WHARF
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110
		BUSINESS PHONE:		6174285150

	MAIL ADDRESS:	
		STREET 1:		C/O PAREXEL INTERNATIONAL CORP
		STREET 2:		195 WEST STREET
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-09-06</periodOfReport>

    <issuer>
        <issuerCik>0000799729</issuerCik>
        <issuerName>PAREXEL INTERNATIONAL CORP</issuerName>
        <issuerTradingSymbol>PRXL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001018241</rptOwnerCik>
            <rptOwnerName>CALLOW A DANA JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>BOSTON MILLENNIA PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>30 ROWES WHARF</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02110</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-09-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>43</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>Douglas A. Batt, Attorney-in-fact</signatureName>
        <signatureDate>2007-09-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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