<SEC-DOCUMENT>0001209191-20-010338.txt : 20200218
<SEC-HEADER>0001209191-20-010338.hdr.sgml : 20200218
<ACCEPTANCE-DATETIME>20200218181202
ACCESSION NUMBER:		0001209191-20-010338
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20200213
FILED AS OF DATE:		20200218
DATE AS OF CHANGE:		20200218

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Kadre Manuel
		CENTRAL INDEX KEY:			0001396538

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12111
		FILM NUMBER:		20626771

	MAIL ADDRESS:	
		STREET 1:		CC1 COMPANIES, INC.
		STREET 2:		220 ALHAMBRA CIRCLE
		CITY:			CORAL GABLES
		STATE:			FL
		ZIP:			33145

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MEDNAX, INC.
		CENTRAL INDEX KEY:			0000893949
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-HOSPITALS [8060]
		IRS NUMBER:				263667538
		STATE OF INCORPORATION:			FL
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1301 CONCORD TERRACE
		CITY:			SUNRISE
		STATE:			FL
		ZIP:			33323
		BUSINESS PHONE:		9543840175

	MAIL ADDRESS:	
		STREET 1:		1301 CONCORD TERRACE
		CITY:			SUNRISE
		STATE:			FL
		ZIP:			33323

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PEDIATRIX MEDICAL GROUP INC
		DATE OF NAME CHANGE:	19950801
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-02-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000893949</issuerCik>
        <issuerName>MEDNAX, INC.</issuerName>
        <issuerTradingSymbol>MD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001396538</rptOwnerCik>
            <rptOwnerName>Kadre Manuel</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1301 CONCORD TERRACE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SUNRISE</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33323</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common  Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-02-13</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4717</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>124313</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Restricted shares granted pursuant to Issuer's Amended and Restated 2008 Incentive Compensation Plan, in connection with annual equity award.  Shares will vest in three equal installments on March 1, 2021, March 1, 2022 and March 1, 2023.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Dominic J. Andreano, Attorney-in-Fact</signatureName>
        <signatureDate>2020-02-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
