PIP: A clinical trial was designed to develop a reversible supression of spermatogenesis with combined injections of long-acting medroxyprogesterone acetate and testosterone cypionate on 30 normal fertile male volunteers for a 15-month period. The objective was to determine the period of time to induce infertility, the minimum maintenance doses, the period of time to recover fertility, and various adverse side effects such as clinical, biological, sexual and hormonal side effects. Group 1 consisted of 10 cases who received 200 mg of long-acting medroxy-progesterone acetate (Depo-Provera, D-P) and 200 mg of long-acting testosterone cypionate (Depo-Testosterone, D-T). The 10 cases in Group 2 received 400 mg of D-P plus 200 mg of D-T. The 10 cases of Group 3 received 200 mg of D_P and 400 mg of D-T. The mean age of the subjects was 38. The clinical trial was divided into 3 phases, and the subjects were instructed to use conventional contraception. The combined steroids compounds used in this trial suppress sperm production to azoospermia or severe oligospermia but could not achieve full suppression in all subjects. This was the case even when high doses of D-P plus D-T were used. For the development of an ideal method of reversible male contraception using sex hormones, a new combination with the lowest dosage of Depo-Provera and Depo-Testosterone should be developed by which full suppression of spermatogenesis could be attained in a limited period of time.