-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 zKMzxl1WmT7BJSuS90MxXQ==

<SEC-DOCUMENT>0000799729-08-000048.txt : 20080717
<SEC-HEADER>0000799729-08-000048.hdr.sgml : 20080717
<ACCEPTANCE-DATETIME>20080717101516
ACCESSION NUMBER:		0000799729-08-000048
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080715
FILED AS OF DATE:		20080717
DATE AS OF CHANGE:		20080717

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:			VON RICKENBACH JOSEF H
		CENTRAL INDEX KEY:			0001007706

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-21244
		FILM NUMBER:		08956159

	BUSINESS ADDRESS:	
		STREET 1:		195 WEST ST
		STREET 2:		C/O PAREXEL INTERNATIONAL CORPORATION
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451-1163
		BUSINESS PHONE:		6174879900

	MAIL ADDRESS:	
		STREET 1:		C/O PAREXEL INTERNATIONAL CORPORATION
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451-1163
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-07-15</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001007706</rptOwnerCik>
            <rptOwnerName>VON RICKENBACH JOSEF H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PAREXEL INTERNATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>200 WEST STREET</rptOwnerStreet2>
            <rptOwnerCity>WALTHAM</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02451</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman &amp; CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-07-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>14800</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.15</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>445605</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-07-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>11900</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>25.3</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>433705</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-07-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2900</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>25.81</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>430805</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options (Right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.15</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-07-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>14800</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2008-08-15</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>14800</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>60418</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F4">Currently exercisable.</footnote>
        <footnote id="F3">This transaction was executed in multiple trades through a trade order executed by a broker-dealer at prices ranging from $25.70-$25.94.  The price reported in this column reflects the weighted average sale price.  For all transactions reported on this Form 4 utilizing a weighted average price, the reporting person will provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares sold at each price.</footnote>
        <footnote id="F1">The reported sale was effected by a broker pursuant to instructions set forth in a Rule 10b5-1 trading plan adopted by the reporting person.</footnote>
        <footnote id="F2">This transaction was executed in multiple trades through a trade order executed by a broker-dealer at prices ranging from $24.69-$25.69.  The price reported in this column reflects the weighted average sale price.  For all transactions reported on this Form 4 utilizing a weighted average price, the reporting person will provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares sold at each price.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>JosefH.von Rickenbach</signatureName>
        <signatureDate>2008-07-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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