<SEC-DOCUMENT>0001140361-14-009652.txt : 20140225
<SEC-HEADER>0001140361-14-009652.hdr.sgml : 20140225
<ACCEPTANCE-DATETIME>20140225213335
ACCESSION NUMBER:		0001140361-14-009652
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20140222
FILED AS OF DATE:		20140225
DATE AS OF CHANGE:		20140225

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CODEXIS INC
		CENTRAL INDEX KEY:			0001200375
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL ORGANIC CHEMICALS [2860]
		IRS NUMBER:				710872999
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		200 PENOBSCOT DRIVE
		CITY:			REDWOOD CITY
		STATE:			CA
		ZIP:			94063
		BUSINESS PHONE:		650-421-8100

	MAIL ADDRESS:	
		STREET 1:		200 PENOBSCOT DRIVE
		CITY:			REDWOOD CITY
		STATE:			CA
		ZIP:			94063

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Yang Patrick Y
		CENTRAL INDEX KEY:			0001309988

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34705
		FILM NUMBER:		14642704

	MAIL ADDRESS:	
		STREET 1:		C/O GENENTECH INC
		STREET 2:		1 DNA WAY,MS 49,ATTN:K.STRAND OR J.BERRY
		CITY:			SOUTH SAN FRANCISCO
		STATE:			CA
		ZIP:			94080-4990
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-02-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001200375</issuerCik>
        <issuerName>CODEXIS INC</issuerName>
        <issuerTradingSymbol>CDXS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001309988</rptOwnerCik>
            <rptOwnerName>Yang Patrick Y</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CODEXIS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>200 PENOBSCOT DRIVE</rptOwnerStreet2>
            <rptOwnerCity>REDWOOD CITY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94063</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2014-02-22</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>52083</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>72083</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Restricted stock. The shares vest as to one third of the shares on each yearly anniversary of February 22, 2014, provided that the Reporting Person provides continuous services to the Issuer as an employee, consultant, director or office through each such vesting date.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Dave Swarthout, Attorney-in-Fact for Patrick Y. Yang</signatureName>
        <signatureDate>2014-02-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
