<SEC-DOCUMENT>0000015615-25-000108.txt : 20250916
<SEC-HEADER>0000015615-25-000108.hdr.sgml : 20250916
<ACCEPTANCE-DATETIME>20250916165536
ACCESSION NUMBER:		0000015615-25-000108
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250911
FILED AS OF DATE:		20250916
DATE AS OF CHANGE:		20250916

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Campbell C Robert
		CENTRAL INDEX KEY:			0001307261
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08106
		FILM NUMBER:		251317944

	MAIL ADDRESS:	
		STREET 1:		800 DOUGLAS ROAD
		STREET 2:		12TH FLOOR
		CITY:			CORAL GABLES
		STATE:			FL
		ZIP:			33134

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MASTEC INC
		CENTRAL INDEX KEY:			0000015615
		STANDARD INDUSTRIAL CLASSIFICATION:	WATER, SEWER, PIPELINE, COMM AND POWER LINE CONSTRUCTION [1623]
		ORGANIZATION NAME:           	05 Real Estate & Construction
		EIN:				650829355
		STATE OF INCORPORATION:			FL
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		800 S. DOUGLAS ROAD
		STREET 2:		10TH FLOOR
		CITY:			CORAL GABLES
		STATE:			FL
		ZIP:			33134
		BUSINESS PHONE:		3055991800

	MAIL ADDRESS:	
		STREET 1:		800 S. DOUGLAS ROAD
		STREET 2:		10TH FLOOR
		CITY:			CORAL GABLES
		STATE:			FL
		ZIP:			33134

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	BURNUP & SIMS INC
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1758056133.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-09-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000015615</issuerCik>
        <issuerName>MASTEC INC</issuerName>
        <issuerTradingSymbol>MTZ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001307261</rptOwnerCik>
            <rptOwnerName>Campbell C Robert</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>4145 PINTA COURT</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CORAL GABLES</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33146</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-09-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>190.39</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>35277</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">These shares were sold in 47 separate transactions, each with a price of $190.39. 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 in each transaction.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>\s\ Alberto de Cardenas For: Robert Campbell</signatureName>
        <signatureDate>2025-09-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
