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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,
 Rxafgy6ToU4OuRz+JkgUCkhkmGfKgdobny1v4R6thj28flta1mmJUe4LT+HAIknQ
 LOcYMvOeUMmN+7vGrUSeSQ==

<SEC-DOCUMENT>0000350894-03-000048.txt : 20031218
<SEC-HEADER>0000350894-03-000048.hdr.sgml : 20031218
<ACCEPTANCE-DATETIME>20031218084930
ACCESSION NUMBER:		0000350894-03-000048
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031216
FILED AS OF DATE:		20031218

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			UJOBAI JOE
		CENTRAL INDEX KEY:			0001191731

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-10200
		FILM NUMBER:		031061200

	BUSINESS ADDRESS:	
		STREET 1:		SEI INVESTMENT INC
		STREET 2:		ONE FREEDOM VALLEY
		CITY:			OAKS
		STATE:			PA
		ZIP:			19456

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SEI CORP
		CENTRAL INDEX KEY:			0000350894
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY BROKERS, DEALERS & FLOTATION COMPANIES [6211]
		IRS NUMBER:				231707341
		STATE OF INCORPORATION:			PA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1 FREEDOM VALLEY DRIVE
		CITY:			OAKS
		STATE:			PA
		ZIP:			19456-1100
		BUSINESS PHONE:		6106761000

	MAIL ADDRESS:	
		STREET 1:		1 FREEDOM VALLEY DRIVE
		CITY:			OAKS
		STATE:			PA
		ZIP:			19456-1100
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-12-16</periodOfReport>
    <issuer>
        <issuerCik>0000350894</issuerCik>
        <issuerName>SEI CORP</issuerName>
        <issuerTradingSymbol>SEIC</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001191731</rptOwnerCik>
            <rptOwnerName>UJOBAI JOE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE FREEDOM VALLEY DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>OAKS</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19456</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Senior Vice President</officerTitle></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Stock Option (Right to Buy)</value></securityTitle><conversionOrExercisePrice><value>29.56</value></conversionOrExercisePrice><transactionDate><value>2003-12-16</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>30000</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2010-12-16</value></exerciseDate><expirationDate><value>2013-12-16</value></expirationDate><underlyingSecurity><underlyingSecurityTitle
><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>30000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>30000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes/><remarks>The option vests upon the earlier of the Issuer's attainment of specific levels of earnings per share or seven years from the date of the grant.  The option will expire on the ten year anniversary of the date of the grant.</remarks><ownerSignature><signatureName>Michelle Vaughn (Attorney-in-Fact)</signatureName><signatureDate>2003-12-18</signatureDate></ownerSignature></ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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