-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Kak+XcwazFkZYhF8TdH/eH5nHTfSfxFyrDT6U3qK0JIYYM3MMqwlSNW9ANRwHyfy
 0Bjyv2S4QO17HPKIZJiN3w==

<SEC-DOCUMENT>0001202823-04-000005.txt : 20040317
<SEC-HEADER>0001202823-04-000005.hdr.sgml : 20040317
<ACCEPTANCE-DATETIME>20040317165311
ACCESSION NUMBER:		0001202823-04-000005
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040315
FILED AS OF DATE:		20040317

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			QUESTAR CORP
		CENTRAL INDEX KEY:			0000751652
		STANDARD INDUSTRIAL CLASSIFICATION:	NATURAL GAS TRANSMISSION & DISTRIBUTION [4923]
		IRS NUMBER:				870407509
		STATE OF INCORPORATION:			UT
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		180 EAST 100 SOUTH ST
		STREET 2:		PO BOX 45433
		CITY:			SALT LAKE CITY
		STATE:			UT
		ZIP:			84145
		BUSINESS PHONE:		8015345000

	MAIL ADDRESS:	
		STREET 1:		180 EAST 100 SOUTH ST
		STREET 2:		P O BOX 45433
		CITY:			SALT LAKE CITY
		STATE:			UT
		ZIP:			84145

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ALLRED ALAN K
		CENTRAL INDEX KEY:			0001202823

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08796
		FILM NUMBER:		04675898

	BUSINESS ADDRESS:	
		STREET 1:		180 EAST 100 S
		STREET 2:		P O BOX 45360
		CITY:			SALT LAKE CITY
		STATE:			UT
		ZIP:			841450360
		BUSINESS PHONE:		8013245768

	MAIL ADDRESS:	
		STREET 1:		180 EAST 100 SOUTH
		STREET 2:		P O BOX 45360
		CITY:			SLT LAKE CITY
		STATE:			UT
		ZIP:			841450360
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-03-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000751652</issuerCik>
        <issuerName>QUESTAR CORP</issuerName>
        <issuerTradingSymbol>STR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001202823</rptOwnerCik>
            <rptOwnerName>ALLRED ALAN K</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>180 EAST 100 SOUTH</rptOwnerStreet1>
            <rptOwnerStreet2>P O BOX 45360</rptOwnerStreet2>
            <rptOwnerCity>SLT LAKE CITY</rptOwnerCity>
            <rptOwnerState>UT</rptOwnerState>
            <rptOwnerZipCode>841450360</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock and attached Common Stock Purchase Rights</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>19899</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock and attached Common Stock Purchase Rights</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>21629.5</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Employee Investment Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>35.44</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-03-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>0.2647</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>35.44</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Phantom Stock Units</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>0.2647</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>387.887</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock and attached Common Stock Purchase Rights</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock and attached Common Stock Purchase Rights</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>85984</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">As of March 12, 2004, I have 21,629.50 equivalent shares of stock in the Employee Investment Plan.</footnote>
        <footnote id="F2">Phantom stock units will be converted to cash beginning at retirement; my retirement date is unknown.</footnote>
        <footnote id="F3">I receive phantom stock units as a result of my participation in an excess benefit Plan.  I have 341.8650 shares in it in addition to my shares in a deferred compensation Plan.  I also receive dividends.</footnote>
        <footnote id="F4">This date is unknown since I am only reflecting my total in common stock and attached common stock purchase rights at this time.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Connie C. Holbrook Attorney in Fact for A.K. Allred</signatureName>
        <signatureDate>2004-03-16</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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