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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>0000945436-08-000010.txt : 20080125
<SEC-HEADER>0000945436-08-000010.hdr.sgml : 20080125
<ACCEPTANCE-DATETIME>20080125174252
ACCESSION NUMBER:		0000945436-08-000010
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080123
FILED AS OF DATE:		20080125
DATE AS OF CHANGE:		20080125

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MEMC ELECTRONIC MATERIALS INC
		CENTRAL INDEX KEY:			0000945436
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				561505767
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		501 PEARL DRIVE
		STREET 2:		P. O. BOX 8
		CITY:			ST. PETERS
		STATE:			MO
		ZIP:			63376
		BUSINESS PHONE:		6364745000

	MAIL ADDRESS:	
		STREET 1:		501 PEARL DRIVE
		STREET 2:		P. O. BOX 8
		CITY:			ST. PETERS
		STATE:			MO
		ZIP:			63376

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CABRERA MIGNON
		CENTRAL INDEX KEY:			0001374133

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13828
		FILM NUMBER:		08551985

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		636-474-5000

	MAIL ADDRESS:	
		STREET 1:		501 PEARL DRIVE
		CITY:			ST PETERS
		STATE:			MO
		ZIP:			63376
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-01-23</periodOfReport>

    <issuer>
        <issuerCik>0000945436</issuerCik>
        <issuerName>MEMC ELECTRONIC MATERIALS INC</issuerName>
        <issuerTradingSymbol>WFR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001374133</rptOwnerCik>
            <rptOwnerName>CABRERA MIGNON</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MEMC ELECTRONIC MATERIALS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 8</rptOwnerStreet2>
            <rptOwnerCity>ST. PETERS,</rptOwnerCity>
            <rptOwnerState>MO</rptOwnerState>
            <rptOwnerZipCode>63376</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP Human Resources</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Commmon Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2008-01-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5000</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>69.84</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-01-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2018-01-23</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit represents a contingent right to receive one share of MEMC common stock. The restricted stock units were awarded on January 23, 2008 under the MEMC 2001 Equity Incentive Plan in a transaction exempt under Rule 16b-3.</footnote>
        <footnote id="F2">Of these 5,000 restricted stock units, up to 2,500 are subject to forfeiture depending on pre-established company earnings targets for 2008.  Of the 5,000 restricted stock units that are not forfeited, 50% vest on January 23, 2011 and the remaining 50% vest on January 23, 2013.</footnote>
        <footnote id="F3">The option to purchase 10,000 shares of common stock was awarded on January 23, 2008 under the MEMC 2001 Equity Incentive Plan in a transaction exempt under Rule 16b-3 and becomes exercisable at an exercise price of $69.84 per share in 25% increments on January 23, 2009, January 23, 2010, January 23, 2011, and January 23, 2012.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Mignon Cabrera</signatureName>
        <signatureDate>2008-01-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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