We retrospectively reviewed the outcome of 37 prostate cancer patients with ureteral obstruction treated by percutaneous nephrostomy. The over-all survival was 57% at 1 year and 29% at 2 years (median survival time 21 months). The 1 and 2-year survival rates of 15 patients with no prior hormonal therapy were 73 and 47%, respectively, while those of patients who had previously received hormonal therapy were 48 and 19%, respectively. Median survival times of these groups were 24 months and 12 months, respectively. Of 12 patients who had severe renal failure before percutaneous nephrostomy (serum creatinine greater than or equal to 6.9 mg. per dl.) 9 had an adequate return of renal function (serum creatinine less than 3 mg. per dl.) after drainage and 58% survived more than 1 year (median survival time 22 months). Percutaneous nephrostomy is safe and effective in relieving ureteral obstruction and reasonable survival can be achieved even in patients with renal failure. Percutaneous nephrostomy should be considered strongly in these patients.