One hundred eighty-three patients with bladder cancer category T3NxMo (the diameter of the primary exceeding 5 cm), were treated by preoperative 40 Gy and simple cystectomy. Using only pretreatment information, the group with the best prognosis was characterized by a T3A-growth with a normal intravenous pyelography, with about a 75% cure rate. Before cystectomy, after irradiation the combination of a clinically assessed radiation-downstaged growth (T40GY less than 3) with normal urography, predicted the best chance of cure at about 80%. After cystectomy was performed, the best prognostic group could be most correctly identified: those patients with both microscopic downstaging of the primary ("P" less than 3) and no vascular invasion in the cystectomy specimen (CV-) combined with normal urography had an 81% chance of cure. This most favorable group constitutes 45% of all patients.