Exhibit 21

MasTec, Inc.

SUBSIDIARIES OF MASTEC, INC.

December 31, 2019

NORTH AMERICA

Cash Construction Company, Inc. (TX)	(100% owned by MasTec North America, Inc.)
EC Source Services, LLC (FL)	(100% owned by MasTec, Inc.)
MasTec Canada, Inc. (Canada)	(100% owned by Pacer Construction Holdings Corporation (Canada)) (100% owned by MasTec Canadian Holdco ULC (Canada)) (100% owned by MasTec Cooperateif (UA))
MasTec Comanche, LLC (FL)	(100% owned by MasTec Pipeline Holdings, LLC)
MasTec Cooperateif (UA) (NL)	(99.99% owned by MasTec North America, Inc.) (0.01% owned by MasTec Foreign Holdings, LLC (FL))
MasTec Lux Foreign Finance S.a r.l.	(100% owned by MasTec FFH, Inc. (FL)) (100% owned by MasTec North America, Inc.)
MasTec Network Solutions, LLC f/k/a Nsoro MasTec, LLC (FL)	(100% owned by MasTec, Inc.)
MasTec North America, Inc. (FL)	(100% owned by MasTec, Inc.)
MasTec Pipeline Holdings, LLC (FL)	(100% owned by MasTec, Inc.)
MasTec TPP, LLC (FL)	(100% owned by MasTec Pipeline Holdings, LLC)
Precision Pipeline LLC (WI)	(100% owned by Precision Acquisition, LLC (WI)) (100% owned by MasTec, Inc.)
Pumpco, Inc. (TX)	(100% owned by MasTec North America, Inc.)
SEFNCO Communications, Inc. (CA)	(100% owned by MasTec North America, Inc.)
Three Phase Line Construction, Inc. (NH)	(100% owned by Three Phase Acquisition Corp. (NH)) (100% owned by MasTec, Inc.)
Wanzek Construction, Inc. (ND)	(100% owned by MasTec North America, Inc.)

Certain other subsidiaries have been omitted because, in the aggregate, they would not constitute a significant subsidiary.