Phase 2 study of 5'-DFUR in bladder and prostatic cancer was conducted at 15 collaborative institutions including Okayama University. 5'-DFUR was orally administered to patients at a daily dose of 800-1200 mg for more than 4 weeks. Forty-one patients with bladder cancer and 12 patients with prostatic cancer were evaluated. The response rate for bladder cancer was 31.7% (CR, 1 case: PR, 12 cases), against no response with prostatic cancer. Moreover, the concentration of 5-FU in bladder tumors was confirmed to be high. Adverse reactions such as diarrhea, anorexia, and nausea were observed. Thus, 5'-DFUR seems to be useful for the treatment of bladder cancer.