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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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 sqieHkR+3DfP+QOqlSVleA==

<SEC-DOCUMENT>0001242609-10-000043.txt : 20100902
<SEC-HEADER>0001242609-10-000043.hdr.sgml : 20100902
<ACCEPTANCE-DATETIME>20100902175731
ACCESSION NUMBER:		0001242609-10-000043
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100831
FILED AS OF DATE:		20100902
DATE AS OF CHANGE:		20100902

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			INTERNATIONAL RECTIFIER CORP /DE/
		CENTRAL INDEX KEY:			0000316793
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				951528961
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0628

	BUSINESS ADDRESS:	
		STREET 1:		233 KANSAS ST
		CITY:			EL SEGUNDO
		STATE:			CA
		ZIP:			90245
		BUSINESS PHONE:		3107268000

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CRANSTON MARY B
		CENTRAL INDEX KEY:			0001104268

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-07935
		FILM NUMBER:		101055845

	MAIL ADDRESS:	
		STREET 1:		C/O GRAFTECH INTERNATIONAL LTD.
		STREET 2:		12900 SNOW ROAD
		CITY:			PARMA
		STATE:			OH
		ZIP:			44130
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-08-31</periodOfReport>

    <issuer>
        <issuerCik>0000316793</issuerCik>
        <issuerName>INTERNATIONAL RECTIFIER CORP /DE/</issuerName>
        <issuerTradingSymbol>IRF</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001104268</rptOwnerCik>
            <rptOwnerName>CRANSTON MARY B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>101 N. SEPULVEDA BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>EL SEGUNDO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90245</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted STock Unit</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-08-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3815</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2011-08-31</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2011-08-31</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3815</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3815</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This grant represents the annual award provided to a non-employee director under Company practice.</footnote>
        <footnote id="F2">Option vests 100% on the first anniversary of grant date.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Mary Cranston</signatureName>
        <signatureDate>2010-09-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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