<SEC-DOCUMENT>0001209191-21-063836.txt : 20211110
<SEC-HEADER>0001209191-21-063836.hdr.sgml : 20211110
<ACCEPTANCE-DATETIME>20211110160734
ACCESSION NUMBER:		0001209191-21-063836
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20211110
FILED AS OF DATE:		20211110
DATE AS OF CHANGE:		20211110

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Hinson Roger Mack
		CENTRAL INDEX KEY:			0001826596

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12111
		FILM NUMBER:		211396585

	MAIL ADDRESS:	
		STREET 1:		C/O MEDNAX, INC.
		STREET 2:		1301 CONCORD TERRACE
		CITY:			SUNRISE
		STATE:			FL
		ZIP:			33323

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>2021-11-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001826596</rptOwnerCik>
            <rptOwnerName>Hinson Roger Mack</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1301 CONCORD TERRACE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SUNRISE</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33323</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Pres., PDX &amp; OBX Medical Group</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-11-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>8800</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>28.38</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>107391</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Sales made pursuant to reporting person's 10b5-1 trading plan adopted June 15, 2021.</footnote>
        <footnote id="F2">The price reported in Column 4 is a weighted average price. The reported securities were sold in multiple transactions with prices ranging from
$28.13 to $28.55 for a weighted average sales price of $28.38. The reporting person undertakes to provide the issuer, any security holder of the
issuer or the staff of the Securities and Exchange Commission upon request, full information regarding the number of shares sold at each
separate price within the range set forth in this footnote.</footnote>
        <footnote id="F3">Includes 62 shares acquired by reporting person through Issuer's Employee Stock Purchase Plan since the last Form 4 filing.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Dominic J. Andreano, Attorney-in-Fact</signatureName>
        <signatureDate>2021-11-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
