The V.A. Cooperative Urological Research Group has been engaged in clinical trials of treatment for prostatic cancer for the past 10 years. The first V.A. study showed a much higher risk of cardiovascular disease in patients receiving 5.0 mg of diethylstilbestrol daily than in those receiving placebo. A second V.A. study was begun to compare these treatments with intermediate (0.2 and 1.0 mg/day) doses of diethylstilbestrol. Analyses of survival and cause of death in the second study are presented for 294 Stage III and 214 Stage IV patients randomly assigned to placebo or one of the 3 doses of diethylstilbestrol. Thus far, the 1.0‐mg dose has been as effective as the 5.0‐mg dose in controlling the prostate cancer, but it does not seem to be associated with the excess risk of cardiovascular death.