In the course of 20 years 83 patients with tumor of the bladder were treated by cystectomy. The infiltrations of the tumors were 14 pT1, 12 pT2, 44 pT3 and 13 pT4. There were metastatic regional lymph nodes in 11 cases (13%). The urinary diversions were 64 ureterosigmoidostomies, 18 ileal conduits and one cutaneous ureterostomy. The perioperative complication rate was 48% and mortality rate was 12%. The 3-year and 5-year survivals were 50% and 44.4%, respectively. Twenty three patients (28%) died as a result of cancer recurrence. Parallel with the increase in the depth of neoplastic bladder wall infiltrations increases were observed in the rates of lymph node metastates and tumorous mortality while a decrease of survival was noted. Owing to the observed significant differences in survival (3-year survivals 12/23 vs 0/4.5-year survivals 9/20 vs 0/2) and tumorous mortality (9/38 vs 4/6) of the T3a and T3b stage patients the authors think it has to be justified to separate the two patient groups as regarding therapy and prognosis. In T3a cases cystectomy is employed as monotherapy, while for T3b cases also adjuvant chemotherapy is recommended. The prognosis of tumors extending over the bladder wall is extremely poor. An exception to this in the bladder cancer infiltrating the prostate following whose extirpation authors have observed more than ten-year survivals in two cases.