The authors report preliminary results of a study performed on six patients with by advanced, hormone-refractory prostate cancer. These patients were treated by estramustine phosphate (10 mg/kg) and methotrexate (60 mg/mq). Low toxicity allows the use of this therapy in outpatient regimens. Moreover, the high rate of partial responses (five patients) shows the remarkable efficacy of this therapy, even if follow-up and number of patients are not sufficient to reach definitive conclusions.