-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 NaUqgc5CXyOrcylCZctMQyo8sPV2SkJfgMoYne9dn8BQvaJzT5HW2Fq4mUUCv21K
 yymlGlsuaItCz+xRBESKqw==

<SEC-DOCUMENT>0000757011-10-000079.txt : 20101001
<SEC-HEADER>0000757011-10-000079.hdr.sgml : 20101001
<ACCEPTANCE-DATETIME>20101001140054
ACCESSION NUMBER:		0000757011-10-000079
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100930
FILED AS OF DATE:		20101001
DATE AS OF CHANGE:		20101001

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Armario Jose
		CENTRAL INDEX KEY:			0001377480

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08864
		FILM NUMBER:		101101827

	MAIL ADDRESS:	
		STREET 1:		MCDONALD'S CORPORATION
		STREET 2:		2915 JORIE BOULEVARD
		CITY:			OAK BROOK
		STATE:			IL
		ZIP:			60523

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
</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>2010-09-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001377480</rptOwnerCik>
            <rptOwnerName>Armario Jose</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>2010-09-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1531.98</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>13.055</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>1531.98</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>32002.2657</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 on September 30, 2010.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Ellis A. Regenbogen, Attorney-In-Fact</signatureName>
        <signatureDate>2010-10-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----