-----BEGIN PRIVACY-ENHANCED MESSAGE-----
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>0000757011-10-000004.txt : 20100104
<SEC-HEADER>0000757011-10-000004.hdr.sgml : 20100101
<ACCEPTANCE-DATETIME>20100104160543
ACCESSION NUMBER:		0000757011-10-000004
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20091231
FILED AS OF DATE:		20100104
DATE AS OF CHANGE:		20100104

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			USG CORP
		CENTRAL INDEX KEY:			0000757011
		STANDARD INDUSTRIAL CLASSIFICATION:	CONCRETE GYPSUM  PLASTER PRODUCTS [3270]
		IRS NUMBER:				363329400
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		550 WEST ADAMS STREET
		STREET 2:		DEPARTMENT 188
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60661
		BUSINESS PHONE:		312-606-4000

	MAIL ADDRESS:	
		STREET 1:		DEPARTMENT #188
		STREET 2:		550 WEST ADAMS STREET
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60661

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LEER STEVEN F
		CENTRAL INDEX KEY:			0001046086
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08864
		FILM NUMBER:		10502316

	MAIL ADDRESS:	
		STREET 1:		USG CORPORATION
		STREET 2:		125 SOUTH FRANKLIN STREET
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000757011</issuerCik>
        <issuerName>USG CORP</issuerName>
        <issuerTradingSymbol>USG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001046086</rptOwnerCik>
            <rptOwnerName>LEER STEVEN F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O USG CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>550 WEST ADAMS STREET</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60661</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Deferred Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7205.6239</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>14.225</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7205.6239</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>28573.0059</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Deferral of compensation for service as a director pursuant to the USG Corporation Deferred Compensation Program for Non-Employee Directors.  Each deferred stock unit represents the right to receive the value of one share of common stock.  The deferred stock units become payable in cash or shares of common stock, at the reporting person's option, following the reporting person's termination of service as a director.</footnote>
        <footnote id="F2">Mean of the high and low sales prices of a share of common stock December 31, 2009.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Ellis A. Regenbogen, Attorney-In-Fact</signatureName>
        <signatureDate>2010-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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