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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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<SEC-DOCUMENT>0001170010-05-000121.txt : 20050729
<SEC-HEADER>0001170010-05-000121.hdr.sgml : 20050729
<ACCEPTANCE-DATETIME>20050729162015
ACCESSION NUMBER:		0001170010-05-000121
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050624
FILED AS OF DATE:		20050729
DATE AS OF CHANGE:		20050729

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CARMAX INC
		CENTRAL INDEX KEY:			0001170010
		STANDARD INDUSTRIAL CLASSIFICATION:	RETAIL-AUTO DEALERS & GASOLINE STATIONS [5500]
		IRS NUMBER:				541821055
		STATE OF INCORPORATION:			VA
		FISCAL YEAR END:			0228

	BUSINESS ADDRESS:	
		STREET 1:		4900 COX ROAD
		CITY:			GLEN ALLEN
		STATE:			VA
		ZIP:			22060
		BUSINESS PHONE:		8047470422

	MAIL ADDRESS:	
		STREET 1:		4900 COX ROAD
		CITY:			GLEN ALLEN
		STATE:			VA
		ZIP:			23060

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			STEMBERG THOMAS
		CENTRAL INDEX KEY:			0001180655

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31420
		FILM NUMBER:		05985093

	BUSINESS ADDRESS:	
		STREET 1:		500 STAPLES DRIVE
		CITY:			FRAMINGTON
		STATE:			MA
		ZIP:			01702
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>c0001180655d20050729f4as2f.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2005-06-24</periodOfReport>

    <dateOfOriginalSubmission>2005-06-27</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001170010</issuerCik>
        <issuerName>CARMAX INC</issuerName>
        <issuerTradingSymbol>KMX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001180655</rptOwnerCik>
            <rptOwnerName>STEMBERG THOMAS</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ATTN: STOCK OPTIONS</rptOwnerStreet1>
            <rptOwnerStreet2>4900 COX ROAD</rptOwnerStreet2>
            <rptOwnerCity>GLEN ALLEN</rptOwnerCity>
            <rptOwnerState>VA</rptOwnerState>
            <rptOwnerZipCode>23060</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options (Right to buy)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>26.38</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-06-24</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3799</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2006-06-23</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-06-24</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3799</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3799</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This amended Form 4 correctly reports the number of shares of Common Stock underlying the stock options and the terms of such options, which have previously been reported on a Form 4 filed by the Reporting Person on June 27, 2005.</footnote>
        <footnote id="F2">The stock options are exercisable with respect to one-third of the underlying shares of Common Stock on the business day immediately preceding each of June 24, 2006, June 24, 2007, and June 24, 2008.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Sherry Neufer</signatureName>
        <signatureDate>2005-07-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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