EXHIBIT 12.1 MASTEC, INC. AND SUBSIDIARIES Computation of Ratio of Earnings to Fixed Charges THREE MONTHS ENDED YEAR ENDED DECEMBER 31, MARCH 31, ----------------------------------------------------------------------- -------------- 1993 1994 1995 1996 1997 1997 1998 ---------- ----------- ---------- ----------- ------------ ---- ---- (Dollars in thousands) Income (loss) from continuing operations before income taxes........................... $7,353 $10,291 $385 $50,719 $63,550 14,308 (17,077) Fixed Charges: Interest expense............... 302 3,846 5,306 11,940 11,920 2,870 5,056 Interest portion of rent expense........................ -- 1,157 1,362 1,681 7,338 565 1,380 ---------- ----------- ---------- ----------- ------------ ------ ------ Total fixed charges............. 302 5,003 6,668 13,621 19,258 3,438 6,436 ---------- ----------- ---------- ----------- ------------ Earnings (for purposes of fixed charges).................. 7,655 15,294 7,053 64,340 82,808 17,746 (1) ---------- ----------- ---------- ----------- ------------ Ratio of earnings to fixed charges......................... 25.3x 3.1x 1.1x 4.7x 4.3x 5.2x (1) (1) Earnings were inadequate to cover fixed charges.