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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-01-23</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001870144</issuerCik>
        <issuerName>Cardio Diagnostics Holdings, Inc.</issuerName>
        <issuerTradingSymbol>CDIO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002006956</rptOwnerCik>
            <rptOwnerName>Burton Paul Frederick</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>872 SHERIDAN ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>EVANSTON</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2024-01-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionTotalValue>
                    <value>50000</value>
                    <footnoteId id="F2"/>
                </transactionTotalValue>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2024-03-31</value>
            </exerciseDate>
            <expirationDate>
                <value>2024-12-31</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityValue>
                    <value>50000</value>
                </underlyingSecurityValue>
            </underlyingSecurity>
            <postTransactionAmounts>
                <valueOwnedFollowingTransaction>
                    <value>50000</value>
                    <footnoteId id="F2"/>
                </valueOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock upon vesting of the RSU.</footnote>
        <footnote id="F2">Subject to continued service with the Issuer on each respective vesting date, the RSUs will vest as follows based on the closing price of the Issuers common stock on each respective vesting date: (i) $12,500 in value on March 31, 2024; (ii) $12,500 in value on June 30, 2024; (iii) $12,500 in value on September 30, 2024; and (iv) $12,500 in value on December 31, 2024.</footnote>
        <footnote id="F3">The RSUs were granted pursuant to the Issuers 2022 Equity Incentive Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Elisa Luqman as attorney-in-fact for Paul Burton</signatureName>
        <signatureDate>2024-02-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
