Experimental chemotherapy with UFT, doxorubicin and cisplatin was performed against human urogenital cancers transplanted subcutaneously into nude mice. The tumor take was confirmed in 33 cell lines of human neoplasms which consisted of 10 renal cell carcinomas, 5 renal pelvic carcinomas, 3 ureteral carcinomas, 8 carcinomas of the urinary bladder, 3 prostatic carcinomas and 4 testicular tumors. These three antitumor agents were administered starting at day 14 after subcutaneous transplantation. These agents were administered following doses as used clinical practice for 6 weeks. Effect was evaluated by the inhibition rate calculated by the mean tumor weights of both treated and untreated groups. These results were as follows: Synergic action by combination therapy was observed 8 strains (6%); reduced effect was found 37 strains (28%) and immutable group was detected 87 strains (66%). Our results suggest that there is a necessity to perform drug sensitivity test for combination therapy as well as sensitivity test for single drug.