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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 Tjy8EIh+ryYr1nXqoQ1YlA==

<SEC-DOCUMENT>0001179110-08-017427.txt : 20080930
<SEC-HEADER>0001179110-08-017427.hdr.sgml : 20080930
<ACCEPTANCE-DATETIME>20080930143501
ACCESSION NUMBER:		0001179110-08-017427
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080926
FILED AS OF DATE:		20080930
DATE AS OF CHANGE:		20080930

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Cleary James F JR
		CENTRAL INDEX KEY:			0001333281

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51468
		FILM NUMBER:		081096985

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		(800) 824-3703

	MAIL ADDRESS:	
		STREET 1:		651 S. STRATFORD DRIVE, SUITE 100
		CITY:			MERIDIAN
		STATE:			ID
		ZIP:			83642

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MWI Veterinary Supply, Inc.
		CENTRAL INDEX KEY:			0001323974
		STANDARD INDUSTRIAL CLASSIFICATION:	WHOLESALE-MEDICAL, DENTAL & HOSPITAL EQUIPMENT & SUPPLIES [5047]
		IRS NUMBER:				020620757
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		651 S. STRATFORD DRIVE
		STREET 2:		SUITE 100
		CITY:			MERIDIAN
		STATE:			ID
		ZIP:			83642
		BUSINESS PHONE:		(800) 824-3703

	MAIL ADDRESS:	
		STREET 1:		651 S. STRATFORD DRIVE
		STREET 2:		SUITE 100
		CITY:			MERIDIAN
		STATE:			ID
		ZIP:			83642

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MWI Holdings, Inc.
		DATE OF NAME CHANGE:	20050415
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-09-26</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001323974</issuerCik>
        <issuerName>MWI Veterinary Supply, Inc.</issuerName>
        <issuerTradingSymbol>MWIV</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001333281</rptOwnerCik>
            <rptOwnerName>Cleary James F JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>651 S. STRATFORD DRIVE, SUITE 100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MERIDIAN</rptOwnerCity>
            <rptOwnerState>ID</rptOwnerState>
            <rptOwnerZipCode>83642</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2008-09-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>165867</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">On September 26, 2008, the Compensation Committee of the Company awarded Mr. Cleary a restricted stock grant of 5,000 shares. Pursuant to the terms of such grant, the shares will vest in equal parts of 1/5 of the total per year, beginning on September 26, 2009.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Ryan Cleverley as attorney-in-fact for James F. Cleary, Jr.</signatureName>
        <signatureDate>2008-09-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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