-----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,
 Dy9cGGJYNm6psMUXt68V1dMZEPcMoHAk4ItEYzh4Q12BRT3VVHNgmTwuO1bSYRk3
 /s6syz285Vyj1zlF8BEWyg==

<SEC-DOCUMENT>0001127602-08-006803.txt : 20080912
<SEC-HEADER>0001127602-08-006803.hdr.sgml : 20080912
<ACCEPTANCE-DATETIME>20080912093816
ACCESSION NUMBER:		0001127602-08-006803
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080911
FILED AS OF DATE:		20080912
DATE AS OF CHANGE:		20080912

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NUCOR CORP
		CENTRAL INDEX KEY:			0000073309
		STANDARD INDUSTRIAL CLASSIFICATION:	STEEL WORKS, BLAST FURNACES  ROLLING MILLS (COKE OVENS) [3312]
		IRS NUMBER:				131860817
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2100 REXFORD RD
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28211
		BUSINESS PHONE:		7043667000

	MAIL ADDRESS:	
		STREET 1:		2100 REXFORD ROAD
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28211

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NUCLEAR CORP OF AMERICA INC
		DATE OF NAME CHANGE:	19680911

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	AZTEC MECHANICAL CONTRACTORS INC
		DATE OF NAME CHANGE:	19660629

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			RUTKOWSKI JOSEPH A
		CENTRAL INDEX KEY:			0001181107

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-04119
		FILM NUMBER:		081068334

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		7043667000

	MAIL ADDRESS:	
		STREET 1:		2100 REXFORD RD
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28211
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-09-11</periodOfReport>

    <issuer>
        <issuerCik>0000073309</issuerCik>
        <issuerName>NUCOR CORP</issuerName>
        <issuerTradingSymbol>NUE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001181107</rptOwnerCik>
            <rptOwnerName>RUTKOWSKI JOSEPH A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1915 REXFORD ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHARLOTTE</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>28211-</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>EXECUTIVE VICE PRESIDENT</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-09-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>8134</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>30.73</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>189890</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>30.73</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-09-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>8134</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2005-09-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2012-02-29</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8134</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>/s/ Kelly J. Wilmoth, attorney-in-fact for Mr. Rutkowski</signatureName>
        <signatureDate>2008-09-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----