From 1981 to 1989, 24 patients with newly diagnosed metastatic prostate cancer received hormone chemotherapy consisting of orchiectomy, diethylstilbestrol diphosphate and cisplatin. The survival rates were compared with those of 17 metastatic prostate cancer patients who were treated with hormone therapy alone. The five-year survival rates for the hormone chemotherapy group and the hormone therapy group were 64.6% and 29.4%, respectively. Based on our findings, it seems likely that hormone chemotherapy is one of the most effective treatments for patients with newly diagnosed metastatic prostate cancer.