Four hundred seventy patients with invasive bladder cancer treated by definitive irradiation (5000 rad or more) and selective systectomy were followed to assess their survival status and bladder function status. (90% were followed for at least 10 years or to death.) The survival rates for these patients were similar to those obtained in studies of preoperative irradiation with compulsory systectomy: 5 and 10 year survival rates were 38 and 22% respectively. Sixty-five to 70% of these survivors lived with healthy, functioning bladders to at least 10 years after treatment. Seventy-five had a selective cystectomy, usually for recurrent desease, with an operative mortality rate of 11%. Pre-irradiation catheterization, used to control bladder distension and to reduce the possibility of geopraphic miss in irradiating the tumour, had no effect on the control of local disease or on the long-term survival of patients. Therefore, definitive irradiation with selective cystectomy warrants serious consideration in treating patients with invasive bladder cancer, especially considering the quality of life and the high proportion of patients who retain functioning bladders.