Seventy patients with muscle-invading bladder carcinoma (clinical stages T2 to T4) who were not candidates for cystectomy were treated with combined cisplatin and full-dose external-beam radiation on a multi-institutional prospective protocol from 1980 through 1985. Thirty-six patients are alive, all but three without evidence of cancer. The complete response rate is 77% in the 62 patients completing planned irradiation and 70% for all patients. Among the complete responders, 73% are currently maintained, and this group has a significantly higher four-year survival than those not having a complete response and those with recurrence of disease—57% vs 11%. The observed high complete response rates in patients in all stages and the high survival rates suggest irradiation plus cisplatin therapy offers an important therapeutic gain over radiation therapy alone for invasive cancer of the bladder. These results encourage further evaluation of combining cisplatin-based, multidrug chemotherapy with irradiation in patients with locally very-advanced bladder tumors who are not suited for surgery.