Androgen blockage, with either orchiectomy or luteinizing hormone releasing hormone (LHRH) analogs combined with an antiandrogen drug, is the standard treatment for metastatic prostate cancer. Flutatr ide is a nonsteroidal antiandrogen drug that is frequently used for total androgen blockage. We report on a 54-yr-old man with metastatic prostate cancer who developed nonoliguric acute renal failure (ARF) during treatment with flutamide. Following discontinuation of flutamide therapy, his renal functions returned to normal limits within 4 wk. After a rechallenge with flutamide, serum levels of BUN and creatinine increased again. His renal function recovered completely after the cessation of the drug for the second time. This observation confirm that ARF may be clearly attributed to flutamide therapy. Although very rare, flutamide-induced ARF should be considered.