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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2022-02-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000944809</issuerCik>
        <issuerName>OPKO HEALTH, INC.</issuerName>
        <issuerTradingSymbol>OPK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000898860</rptOwnerCik>
            <rptOwnerName>FROST PHILLIP MD ET AL</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>OPKO HEALTH, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4400 BISCAYNE BLVD.</rptOwnerStreet2>
            <rptOwnerCity>MIAMI</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33137</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO &amp; Chairman</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001380896</rptOwnerCik>
            <rptOwnerName>Frost Gamma Investments Trust</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>4400 BISCAYNE BLVD.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MIAMI</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33137</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
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            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

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                <value>Common Stock</value>
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                <natureOfOwnership>
                    <value>See Footnote</value>
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            </ownershipNature>
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                    <value>See Footnote</value>
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                    <value>608</value>
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                    <value>See Footnote</value>
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                    <value>I</value>
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                <natureOfOwnership>
                    <value>See Footnote</value>
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            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
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                <value></value>
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                <transactionPricePerShare>
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                    <value>I</value>
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                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
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            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
                <value>2022-02-14</value>
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                <transactionShares>
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                <transactionPricePerShare>
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                    <value>See Footnote</value>
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                <value>Common Stock</value>
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                    <value>See Footnote</value>
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                <directOrIndirectOwnership>
                    <value>I</value>
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                <natureOfOwnership>
                    <value>See Footnote</value>
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                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
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            <securityTitle>
                <value>Common Stock</value>
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                    <value>300</value>
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                    <value>I</value>
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                    <value>See Footnote</value>
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                </natureOfOwnership>
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                <value>Common Stock</value>
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                <value>2022-02-14</value>
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                <transactionShares>
                    <value>12400</value>
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                <transactionPricePerShare>
                    <value>3.055</value>
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                    <value>A</value>
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                    <value>193768194</value>
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                <directOrIndirectOwnership>
                    <value>I</value>
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                <natureOfOwnership>
                    <value>See Footnote</value>
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            <securityTitle>
                <value>Common Stock</value>
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                <equitySwapInvolved>0</equitySwapInvolved>
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                <value></value>
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                <transactionShares>
                    <value>3500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.06</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
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                <sharesOwnedFollowingTransaction>
                    <value>193771694</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
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        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30127177</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The securities are held by Frost Gamma Investments Trust, of which Phillip Frost M.D., is the trustee.  Frost Gamma L.P. is the sole and exclusive beneficiary of Frost Gamma Investments Trust.  Dr. Frost is one of two limited partners of Frost Gamma L.P.  The general partner of Frost Gamma L.P. is Frost Gamma, Inc., and the sole shareholder of Frost Gamma, Inc. is Frost-Nevada Corporation.  Dr. Frost is also the sole shareholder of Frost-Nevada Corporation.  The reporting person disclaims beneficial ownership of these securities, except to the extent of any pecuniary interest therein and this report shall not be deemed an admission that the reporting person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose.</footnote>
        <footnote id="F2">These securities are held by Frost Nevada Investments Trust, of which the Reporting Person is the trustee and Frost-Nevada, L.P. is the sole and exclusive beneficiary.  The Reporting Person is one of seven limited partners of Frost-Nevada, L.P. and the sole shareholder of Frost-Nevada Corporation, the sole general partner of Frost-Nevada, L.P.  The reporting person disclaims beneficial ownership of these securities, except to the extent of any pecuniary interest therein and this report shall not be deemed an admission that the reporting person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Phillip Frost, M.D., Individually and as Trustee</signatureName>
        <signatureDate>2022-02-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
