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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,
 DAMFdSmwYVWeZ7aRSDY4J3oIdPTEEhoh1wGPxvRfRaTlU5b+KLK7bpzPWoO+7zHo
 UA9AvjcNf3oLJmq4G0JEDw==

<SEC-DOCUMENT>0001179110-05-016726.txt : 20050819
<SEC-HEADER>0001179110-05-016726.hdr.sgml : 20050819
<ACCEPTANCE-DATETIME>20050819170148
ACCESSION NUMBER:		0001179110-05-016726
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050818
FILED AS OF DATE:		20050819
DATE AS OF CHANGE:		20050819

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Berg David P
		CENTRAL INDEX KEY:			0001324454

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09595
		FILM NUMBER:		051039170

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		(612)291-7415

	MAIL ADDRESS:	
		STREET 1:		7601 PENN AVENUE SOUTH
		CITY:			RICHFIELD
		STATE:			MN
		ZIP:			55423

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			BEST BUY CO INC
		CENTRAL INDEX KEY:			0000764478
		STANDARD INDUSTRIAL CLASSIFICATION:	RETAIL-RADIO TV & CONSUMER ELECTRONICS STORES [5731]
		IRS NUMBER:				410907483
		STATE OF INCORPORATION:			MN
		FISCAL YEAR END:			0301

	BUSINESS ADDRESS:	
		STREET 1:		7601 PENN AVE SOUTH
		CITY:			RICHFIELD
		STATE:			MN
		ZIP:			55423
		BUSINESS PHONE:		6122911000

	MAIL ADDRESS:	
		STREET 1:		7601 PENN AVE SOUTH
		CITY:			RICHFIELD
		STATE:			MN
		ZIP:			55423

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	BEST BUYS CO INC
		DATE OF NAME CHANGE:	19900809
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-08-18</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000764478</issuerCik>
        <issuerName>BEST BUY CO INC</issuerName>
        <issuerTradingSymbol>BBY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001324454</rptOwnerCik>
            <rptOwnerName>Berg David P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7601 PENN AVENUE SOUTH</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>RICHFIELD</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55423</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP - Operations</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-08-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>750</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>48.84</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>750</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>31</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401(k) plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>/s/ Matthew J. Norman                    Attorney-in-fact for David P. Berg</signatureName>
        <signatureDate>2005-08-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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