Exhibit 21.1 Set forth below is a list of the significant subsidiaries of the Company. Burnup & Sims of Texas, Inc. Burnup & Sims Telcom of Florida, Inc. Church & Tower, Inc. Church & Tower Fiber Tel, Inc. Church & Tower of TN, Inc. Harrison-Wright Co., Inc. Kennedy Cable Construction, Inc. LatLink Corporation MasTec ComTec of California, Inc. MasTec ComTec of the Carolinas, Inc. MasTec International, Inc. MasTec Technologies, Inc. R.D. Moody & Associates, Inc. Shanco Corporation Sistemas e Instalaciones de Telecomunicacion, S.A. Aidco, Inc. B&D Contractors of Shelby, Inc. C & S Directional Boring, Inc. E.L. Dalton & Company, Inc. M. E. Hunter & Associates, Inc. Phasecom Systems, Inc. Weeks Construction Company Wilde construction, Inc. MasTecInepar S/A Sistemas de Telecomunicacoes