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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001187613-03-000001.txt : 20030722
<SEC-HEADER>0001187613-03-000001.hdr.sgml : 20030722
<ACCEPTANCE-DATETIME>20030722162040
ACCESSION NUMBER:		0001187613-03-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030718
FILED AS OF DATE:		20030722

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ON ASSIGNMENT INC
		CENTRAL INDEX KEY:			0000890564
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-HELP SUPPLY SERVICES [7363]
		IRS NUMBER:				954023433
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		26651 WEST AGOURA ROAD
		CITY:			CALABASAS
		STATE:			CA
		ZIP:			91302
		BUSINESS PHONE:		8188787900

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TATUM MICHAEL ALAN
		CENTRAL INDEX KEY:			0001187613

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-20540
		FILM NUMBER:		03796662

	BUSINESS ADDRESS:	
		STREET 1:		3371 HAMPTON COURT
		CITY:			THOUSAND OAKS
		STATE:			CA
		ZIP:			913621130
		BUSINESS PHONE:		8188783136

	MAIL ADDRESS:	
		STREET 1:		3371 HAMPTON COURT
		CITY:			THOUSANDS OAKS
		STATE:			CA
		ZIP:			91362
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-07-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000890564</issuerCik>
        <issuerName>ON ASSIGNMENT INC</issuerName>
        <issuerTradingSymbol>ASGN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001187613</rptOwnerCik>
            <rptOwnerName>TATUM MICHAEL ALAN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr. V.P. North America</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeSecurity>
        <securityTitle>
            <value>Incentive Stock Option (right to buy)</value>
        </securityTitle>
        <conversionOrExercisePrice>
            <value>5.25</value>
        </conversionOrExercisePrice>
        <transactionDate>
            <value>2003-07-18</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>A</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionAmounts>
            <transactionShares>
                <value>20288</value>
            </transactionShares>
            <transactionValue>
                <value>0</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <exerciseDate>
            <value>2003-08-18</value>
                <footnoteId id="F1"/>
        </exerciseDate>
        <expirationDate>
            <value>2013-07-18</value>
        </expirationDate>
        <underlyingSecurity>
            <underlyingSecurityTitle>
                <value>Common Stock</value>
            </underlyingSecurityTitle>
            <underlyingSecurityShares>
                <value>20288</value>
            </underlyingSecurityShares>
        </underlyingSecurity>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>20288</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </derivativeSecurity>

    <derivativeSecurity>
        <securityTitle>
            <value>Non-Qualified Stock Option (right to buy)</value>
        </securityTitle>
        <conversionOrExercisePrice>
            <value>5.25</value>
        </conversionOrExercisePrice>
        <transactionDate>
            <value>2003-07-18</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>A</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionAmounts>
            <transactionShares>
                <value>64712</value>
            </transactionShares>
            <transactionValue>
                <value>0</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <exerciseDate>
            <value>2003-08-18</value>
                <footnoteId id="F1"/>
        </exerciseDate>
        <expirationDate>
            <value>2013-07-18</value>
        </expirationDate>
        <underlyingSecurity>
            <underlyingSecurityTitle>
                <value>Common Stock</value>
            </underlyingSecurityTitle>
            <underlyingSecurityShares>
                <value>64712</value>
            </underlyingSecurityShares>
        </underlyingSecurity>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>64712</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </derivativeSecurity>

    <footnotes>
        <footnote id="F1">These options vest one forty-eighth after one month from the grant date, and one forty-eighth of such amount with respect to each month thereafter.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: Power of Attorney, Ronald Rudolph, CFO  For: Michael A. Tatum</signatureName>
        <signatureDate>2003-07-22</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----