Twenty-two orchiectomized men with progressive stage D2 prostate cancer were treated with a 3-week cycle of estramustine phosphate (EMP: from day 3 to day 21) and androgen priming (from day 1 to day 4). A partial response according to the NPCP-USA criteria was shown in 4 of 20 evaluable patients. Median progression-free survival of all patients was 24 weeks (range, 4-48) and median survival, 42 weeks (range, 4-112). Although in two cases treatment had to be stopped due to a marked increase in bone pain, no life-threatening side effects were observed. The androgen sensitivity of tumors was supported by the occurrence of increase in prostatic phosphatase and in bone pain in most patients. In this group of patients, androgen priming did not seem to potentiate the effectiveness of EMP, our results being comparable to those previously reported using EMP alone.