Experimental chemotherapy with UFT was performed against human urogenital cancers, transplanted subcutaneously and under the subrenal capsule (SRC) of nude mice. The tumor take with subcutaneous assay was confirmed in 21 cell lines of human neoplasms, which consisted of 9 renal cell carcinomas, 5 renal pelvic carcinomas, 1 ureteral carcinoma, 3 carcinomas of the urinary bladder, 2 prostatic carcinomas and 1 testicular tumor. On the other hand, the tumor take with subrenal capsule assay was confirmed in 17 of the neoplasm, which consisted of 7 renal cell carcinomas, 4 renal pelvic carcinomas, 4 carcinomas of urinary bladder, 1 prostatic carcinoma and 1 testicular tumor. UFT was administered, starting on Day 14 for subcutaneous transplantation and starting on Day 0 for SRC assay. The dose of UFT was the same as clinical dose for both subcutaneous transplantation and subrenal capsule assays. Treatment with UFT was performed for 6 weeks in subcutaneous transplantation assay and for 4 weeks in subrenal capsule assay. Effect of UFT was evaluated by the inhibition rate (IR) calculated by the mean tumor weights of both treated and untreated groups. Responses to the treatment in subcutaneous transplantation and subrenal capsule assays were judged as effective when the IR were higher than 58% and 20%, respectively. Responses rates of UFT in subcutaneous transplantation and subrenal capsule assays were 43% and 82%, respectively.