The efficacy of modified M-VAC chemotherapy was evaluated in twenty-two patients with advanced urothelial carcinoma (18 cases of transitional cell carcinoma, 3 of transitional cell associated with squamous cell carcinoma and 1 of squamous cell carcinoma). Among the 22 patients, 14 underwent two or more courses of modified M-VAC chemotherapy and had lesions suitable for the evaluation. Three of the 14 patients achieved complete response and 6 partial response, resulting in a 64.3% response rate. With regard to the direct effect according to the site of the lesion, the response rate was 75% for the urinary bladder, 100% for lung, 100% for subcutaneous tissues, and 75% for lymph nodes metastasis, whereas the chemotherapy was ineffective for metastasis in the bone and muscle. With this neoadjuvant chemotherapy the primary tumor of the urinary bladder was downstaged from T2 to T0 in one patient who showed complete response. In 4 of 5 patients achieving partial response, the primary tumors were downstaged from T2 to T1. Of 9 patients given this chemotherapy for metastatic lesions, 2 achieved complete response and are alive, whereas all 3 without response died of cancer within the 1 year following the chemotherapy. Since most of the cases associated with the squamous cells carcinoma component showed no response to the therapy, it seems that the level of serum squamous cell carcinoma-associated antigen may be helpful for predicting the efficacy of modified M-VAC chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)