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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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 hjkmKb3f77vE/8LmtgRy/Q==

<SEC-DOCUMENT>0001140361-07-020365.txt : 20071024
<SEC-HEADER>0001140361-07-020365.hdr.sgml : 20071024
<ACCEPTANCE-DATETIME>20071024211147
ACCESSION NUMBER:		0001140361-07-020365
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20071022
FILED AS OF DATE:		20071024
DATE AS OF CHANGE:		20071024

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			U.S. Auto Parts Network, Inc.
		CENTRAL INDEX KEY:			0001378950
		STANDARD INDUSTRIAL CLASSIFICATION:	RETAIL-AUTO & HOME SUPPLY STORES [5531]
		IRS NUMBER:				680623433
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		17150 SOUTH MARGAY AVENUE
		CITY:			CARSON
		STATE:			CA
		ZIP:			90746
		BUSINESS PHONE:		(310) 715-6666

	MAIL ADDRESS:	
		STREET 1:		17150 SOUTH MARGAY AVENUE
		CITY:			CARSON
		STATE:			CA
		ZIP:			90746

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SCHWARTZ JEFFREY A
		CENTRAL INDEX KEY:			0001204970

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33264
		FILM NUMBER:		071189242

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		310-719-8666

	MAIL ADDRESS:	
		STREET 1:		C/O U.S. AUTO PARTS NETWORKS INC.
		STREET 2:		17150 SOUTH MARGAY AVE
		CITY:			CARSON
		STATE:			CA
		ZIP:			90746
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-10-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001378950</issuerCik>
        <issuerName>U.S. Auto Parts Network, Inc.</issuerName>
        <issuerTradingSymbol>PRTS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001204970</rptOwnerCik>
            <rptOwnerName>SCHWARTZ JEFFREY A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O U.S. AUTO PARTS NETWORK, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>17150 SOUTH MARGAY AVENUE</rptOwnerStreet2>
            <rptOwnerCity>CARSON</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90746</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Option (right to buy)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>8.05</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-10-22</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>45000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2008-10-22</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-10-21</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>45000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>45000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Granted pursuant to the U.S. Auto Parts Network, Inc. 2007 Omnibus Incentive Plan.</footnote>
        <footnote id="F2">Thirty-three percent (33%) of the option shares vest and become exercisable upon the first anniversary of the date of grant, and thereafter the balance of the option shares vest and become exercisable in a series of twenty-four equal monthly installments over the two year period measured from the one year anniversary of the date of grant.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jeffrey A Schwartz</signatureName>
        <signatureDate>2007-10-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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