This study was carried out to investigate the changes occurnng In the levels of serum testosterone in the rams given PGF2a, furosemlCl, indomethacin and the combination of this drugs. In the study, 70 Akkaraman rams, approximately 2 years old were used. PGF2a (0.1, 0.2 and 0.3 mg!kg), furosemid (2.0, 4.0 and 6.0 mglkg), in· domethacin (3.0, 6.0 and 9.0 mglkg) and the combinations of these drugs were Intramuscularly given the animals in one dose and in doses following on each other's four days. The blood samples were collected after drug ad· ministrations. Testosterone levels were determined by enzyme immunoassay analyser. The mean testosterone levels in the serum were determined to decrease 641, 528, 382 ngldl and 507, 343, 317 ngldl in the rams given In one dose and in doses following on each other's four days PGF20., according to doses. respectively. On the olher hand, it was established to reduce in the mean serum testosterone levels that turosemid also was given in one dose and in doses following on each other's four days in rams. However, the mean testosterone levels In the serum were determined to increase 926.953,993 ngldl and 950, 1019, 1240 ngldl in the rams given in one dose and In doses following on each other's four days indomethacin, respectively. In conclusion, PGF2u and furosemid were defined to decrease the levels of serum testosterone in the rams, depend on lime and doses. In contrast, indomethacin was established to increase the levels of serum testosterone in the rams.