<SEC-DOCUMENT>0000726958-20-000054.txt : 20200604
<SEC-HEADER>0000726958-20-000054.hdr.sgml : 20200604
<ACCEPTANCE-DATETIME>20200604192928
ACCESSION NUMBER:		0000726958-20-000054
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20200602
FILED AS OF DATE:		20200604
DATE AS OF CHANGE:		20200604

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			REBELEZ DARREN M
		CENTRAL INDEX KEY:			0001484697

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34700
		FILM NUMBER:		20944131

	MAIL ADDRESS:	
		STREET 1:		1722 ROUTH STREET
		STREET 2:		SUITE 1000
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75201-2502

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CASEYS GENERAL STORES INC
		CENTRAL INDEX KEY:			0000726958
		STANDARD INDUSTRIAL CLASSIFICATION:	RETAIL-AUTO DEALERS & GASOLINE STATIONS [5500]
		IRS NUMBER:				420935283
		STATE OF INCORPORATION:			IA
		FISCAL YEAR END:			0430

	BUSINESS ADDRESS:	
		STREET 1:		PO BOX 3001
		CITY:			ANKENY
		STATE:			IA
		ZIP:			50021
		BUSINESS PHONE:		515-965-6100

	MAIL ADDRESS:	
		STREET 1:		PO BOX 3001
		CITY:			ANKENY
		STATE:			IA
		ZIP:			50021
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_159131335123124.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-06-02</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000726958</issuerCik>
        <issuerName>CASEYS GENERAL STORES INC</issuerName>
        <issuerTradingSymbol>CASY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001484697</rptOwnerCik>
            <rptOwnerName>REBELEZ DARREN M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE SE CONVENIENCE BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ANKENY</rptOwnerCity>
            <rptOwnerState>IA</rptOwnerState>
            <rptOwnerZipCode>50021</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted stock units</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2020-06-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>6280</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6280.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6280</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted stock units</value>
                <footnoteId id="F3"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>24999.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24999</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted stock units</value>
                <footnoteId id="F4"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4241.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4241</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Pursuant to terms and conditions of 2018 Stock Incentive Plan. This award will vest in equal installments on June 15, 2021, June 15, 2022 and June 15, 2023. Not included in the reported award amount is a target amount of performance-based restricted stock units that will vest on June 15, 2023, but which are subject to the satisfaction of certain performance criteria other than solely the price of Casey's Common Stock; the final amount of shares earned, if any, will be reported upon vest and satisfaction of those performance measures.</footnote>
        <footnote id="F2">Each restricted stock unit represents the right to receive, following vesting, one share of Common Stock.</footnote>
        <footnote id="F3">Pursuant to terms and conditions of Mr. Rebelez's &quot;make-whole award&quot; of June 24, 2019, granted in conjunction with his commencement of employment as Casey's President and CEO. These units vest over a three-year period in equal installments on each of the first three anniversaries of the grant date.  Not included in the reported award amount is a target amount of performance-based restricted stock units that will vest on June 24, 2022, but which are subject to the satisfaction of certain performance criteria other than solely the price of Casey's Common Stock; the final amount of shares earned, if any, will be reported upon vest and satisfaction of those performance measures.</footnote>
        <footnote id="F4">Pursuant to terms and conditions of 2018 Stock Incentive Plan. This award will vest in full on June 24, 2022. Not included in the reported award amount is a target amount of performance-based restricted stock units that will vest on June 24, 2022, but which are subject to the satisfaction of certain performance criteria other than solely the price of Casey's Common Stock; the final amount of shares earned, if any, will be reported upon vest and satisfaction of those performance measures.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Scott Faber, under Power of Attorney dated June 24, 2019</signatureName>
        <signatureDate>2020-06-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
