<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2014-01-28</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001490660</issuerCik>
        <issuerName>Marketo, Inc.</issuerName>
        <issuerTradingSymbol>MKTO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001599116</rptOwnerCik>
            <rptOwnerName>Sloan Stephen M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>901 MARINERS ISLAND BLVD.</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 200</rptOwnerStreet2>
            <rptOwnerCity>SAN MATEO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94404</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP, Products and Engineering</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>60000</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>32.99</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2023-11-14</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>50000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares of common stock that are issuable pursuant to two Restricted Stock Unit (RSU) awards. The first RSU award provides for vesting as follows: 8,750 shares will vest on each of July 15, 2014, July 15, 2015, July 15, 2016, and July 15, 2017, subject to the grantee continuing to be a service provider through each such date. The second RSU award provides for vesting as follows: 6,250 shares will vest on each of November 15, 2014, November 15, 2015, November 15, 2016, and November 15, 2017,subject to the grantee continuing to be a service provider through each such date.</footnote>
        <footnote id="F2">The option provides for vesting as follows: 25% of the shares will vest on November 15, 2014, and the remainder of the shares will vest in equal installments each month thereafter until the option is fully vested on November 15, 2017.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: Margaretta Smith For: Stephen M. Sloan</signatureName>
        <signatureDate>2014-02-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
