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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>0001140361-09-023969.txt : 20091028
<SEC-HEADER>0001140361-09-023969.hdr.sgml : 20091028
<ACCEPTANCE-DATETIME>20091028160723
ACCESSION NUMBER:		0001140361-09-023969
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20091007
FILED AS OF DATE:		20091028
DATE AS OF CHANGE:		20091028

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Evans Gregory E
		CENTRAL INDEX KEY:			0001319683

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-29187-87
		FILM NUMBER:		091141856

	MAIL ADDRESS:	
		STREET 1:		1000 LOUISIANA STREET
		STREET 2:		SUITE 1500
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77002

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CARRIZO OIL & GAS INC
		CENTRAL INDEX KEY:			0001040593
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				760415919
		STATE OF INCORPORATION:			TX
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1000 LOUISIANA STREET
		STREET 2:		SUITE 1500
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77002
		BUSINESS PHONE:		7133281000

	MAIL ADDRESS:	
		STREET 1:		1000 LOUISIANA STREET
		STREET 2:		SUITE 1500
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77002
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-10-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001040593</issuerCik>
        <issuerName>CARRIZO OIL &amp; GAS INC</issuerName>
        <issuerTradingSymbol>CRZO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001319683</rptOwnerCik>
            <rptOwnerName>Evans Gregory E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1000 LOUISIANA STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1500</rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77002</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP-Exploration</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-10-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1737</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>37651</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Total amount of securities benefically owned following the reported transaction takes into account the disposition of common stock on October 8, 2009 which had already been reported on another Form 4.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/Paul F. Boling, attorney-in-fact</signatureName>
        <signatureDate>2009-10-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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