<SEC-DOCUMENT>0001209191-22-002411.txt : 20220107
<SEC-HEADER>0001209191-22-002411.hdr.sgml : 20220107
<ACCEPTANCE-DATETIME>20220107162827
ACCESSION NUMBER:		0001209191-22-002411
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20220105
FILED AS OF DATE:		20220107
DATE AS OF CHANGE:		20220107

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MEDEL ROGER MD
		CENTRAL INDEX KEY:			0001093125

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12111
		FILM NUMBER:		22518475

	MAIL ADDRESS:	
		STREET 1:		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>2022-01-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001093125</rptOwnerCik>
            <rptOwnerName>MEDEL ROGER MD</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>2022-01-05</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>12639</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>27.42</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>839450</value>
                </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 August 25, 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 $26.99 to $27.63 for a weighted average sales price of $27.42. 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>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Dominic J. Andreano, Attorney-in-Fact</signatureName>
        <signatureDate>2022-01-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
