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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 KWUTck/X5d8l6ZMMD8aklZm7pXpElHe1KW6BlLOYw1+lkYtYrEtvnyh0hgLVhiOg
 u74925ZPvQ1lRcl0F7B14Q==

<SEC-DOCUMENT>0001249701-08-000007.txt : 20080214
<SEC-HEADER>0001249701-08-000007.hdr.sgml : 20080214
<ACCEPTANCE-DATETIME>20080214170552
ACCESSION NUMBER:		0001249701-08-000007
CONFORMED SUBMISSION TYPE:	5
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20071231
FILED AS OF DATE:		20080214
DATE AS OF CHANGE:		20080214

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			LSI CORP
		CENTRAL INDEX KEY:			0000703360
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				942712976
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1621 BARBER LANE
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035
		BUSINESS PHONE:		4084338000

	MAIL ADDRESS:	
		STREET 1:		1621 BARBER LANE
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	LSI LOGIC CORP
		DATE OF NAME CHANGE:	19920703

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MANCUSO MICHAEL J.
		CENTRAL INDEX KEY:			0001222199

	FILING VALUES:
		FORM TYPE:		5
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10317
		FILM NUMBER:		08618559

	BUSINESS ADDRESS:	
		STREET 1:		GENERAL DYNAMICS CORP
		STREET 2:		3190 FAIRVIEW PARK DR
		CITY:			FALLS CHURCH
		STATE:			VA
		ZIP:			22042
		BUSINESS PHONE:		7038763078

	MAIL ADDRESS:	
		STREET 1:		GENERAL DYNAMICS CORPORATION
		STREET 2:		2941 FAIRVIEW PARK DRIVE, SUITE 100
		CITY:			FALLSCHURCH
		STATE:			VA
		ZIP:			22042

	FORMER NAME:	
		FORMER CONFORMED NAME:	MANCUSCO MICHAEL J
		DATE OF NAME CHANGE:	20030307
</SEC-HEADER>
<DOCUMENT>
<TYPE>5
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2007-12-31</periodOfReport>

    <form3HoldingsReported>1</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000703360</issuerCik>
        <issuerName>LSI CORP</issuerName>
        <issuerTradingSymbol>NYSE:LSI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001222199</rptOwnerCik>
            <rptOwnerName>MANCUSO MICHAEL J.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O LSI CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>1621 BARBER LANE</rptOwnerStreet2>
            <rptOwnerCity>MILPITAS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95035</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionCoding>
                <transactionFormType>3</transactionFormType>
                <footnoteId id="F1"/>
            </transactionCoding>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8076</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Reporting person omitted 300 shares from the original Form 3.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Susan Solner Janjigian, by power of attorney</signatureName>
        <signatureDate>2008-02-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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