[en] Intraoperative radiotherapy using large-dose electron irradiation was performed as a radical treatment for superficial bladder cancer on 117 patients. Most of these patients also received additional fractionated external high energy X-ray irradiation convering the whole bladder. The five-year survival rates were 85.2 % in cases with Type I tumors and 64.3 % in those with Type II. Rate of recurrence was 8.0 % for patients with single tumors and 27.0 % for those with multiple tumors. No serious side effects were observed. Because of this low rate of recurrence, and because normal bladder function was usually well preserved, intraoperative radiotherapy is recommended as a superior treatment for superficial bladder cancer. (author)