An unexpectedly high rate of long-term survivors in acute myeloid leukemia (AML) has been observed in a group of patients who achieved a first complete remission (CR) after induction of a therapeutic regimen including daunorubidomycine, vincristine, prednisone and stanozolol, and anabolizing steroid. The rate of CR was 52%. Maintenance therapy was very simple and the only association with stanozolol during this period suggested to us that an androgen, at low dosages, might be responsible for the unusual long-term survival time (45 months with a 95% confidence limit from 30 to 86 months). On the basis of our first observation, high dosages of the androgen were used during the induction phase of treatment but failed to demonstrate any advantage when associated with a drug regimen, including cytosine arabinoside (ARA-C). The reevaluation of each parameter for our group of patients did not allow selection of patients in terms of their age or the hematologic data obtained at presentation. Effects of androgen on the socalled normal hemopoietic cells and on the leukemic cells are discussed, particularly the possible antagonistic effect with ARA-C. A prospective statement is made concerning the possible condition of the prolongation of the complete remission in AML according to some experimental data which enforce the stimulative activity of androgen on the myeloid proliferation.