EXHIBIT 5.1

February 25, 1997

MasTec, Inc.
3155 N.W. 77th Avenue
Miami, Florida 33122-1205

RE:     Registration Statement on Form S-8 of MasTec, Inc.

Dear sir or madam:

        I am Senior Vice President and General Counsel to MasTec, Inc., a
Delaware corporation (the "Company"). I have reviewed the referenced
registration statement relating to the registration by the Company of up to
1,900,000 shares of the Company's voting common stock, $.10 par value (the
"Shares"). It is my opinion that the Shares have been duly and validly
authorized and, when issued, delivered and paid for, will be validly issued,
fully paid and nonassessable.

        I consent to the use of this opinion in the referenced registration
statement.

Sincerely,



/s/ JOSE M. SARIEGO
- ----------------------
Jose M. Sariego
Senior Vice President
and General Counsel