<SEC-DOCUMENT>0000711377-25-000068.txt : 20251028
<SEC-HEADER>0000711377-25-000068.hdr.sgml : 20251028
<ACCEPTANCE-DATETIME>20251028155130
ACCESSION NUMBER:		0000711377-25-000068
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20251027
FILED AS OF DATE:		20251028
DATE AS OF CHANGE:		20251028

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			RODRIGUEZ RAFAEL A
		CENTRAL INDEX KEY:			0001167293
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-17988
		FILM NUMBER:		251424665

	MAIL ADDRESS:	
		STREET 1:		620 LESHER PLACE
		CITY:			LANSING
		STATE:			MI
		ZIP:			48912

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NEOGEN CORP
		CENTRAL INDEX KEY:			0000711377
		STANDARD INDUSTRIAL CLASSIFICATION:	IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES [2835]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				382367843
		STATE OF INCORPORATION:			MI
		FISCAL YEAR END:			0531

	BUSINESS ADDRESS:	
		STREET 1:		620 LESHER PLACE
		CITY:			LANSING
		STATE:			MI
		ZIP:			48912
		BUSINESS PHONE:		5173729200

	MAIL ADDRESS:	
		STREET 1:		620 LESHER PLACE
		CITY:			LANSING
		STATE:			MI
		ZIP:			48912
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-10-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000711377</issuerCik>
        <issuerName>NEOGEN CORP</issuerName>
        <issuerTradingSymbol>NEOG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001167293</rptOwnerCik>
            <rptOwnerName>RODRIGUEZ RAFAEL A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>620 LESHER PLACE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LANSING</rptOwnerCity>
            <rptOwnerState>MI</rptOwnerState>
            <rptOwnerZipCode>48912</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-10-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1777</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.19</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20821</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.19</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2025-10-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1777</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.19</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2025-10-27</value>
            </exerciseDate>
            <expirationDate>
                <value>2025-10-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1777</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1777</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <remarks>Each RSU is the economic equivalent of one share of common stock. On October 27, 2025, these RSUs vested and were settled for an equal number of shares of common stock.</remarks>

    <ownerSignature>
        <signatureName>Christopher Sefcheck (Attorney in Fact)</signatureName>
        <signatureDate>2025-10-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
