The orthotopic ileal neobladder is a completely detubularized, low pressure, high capacity reservoir created from the ileum without any valve. After cystoprostatectomy, a bowel segment of 40-60 cms is dissected free at a distance of 15 cms from the ileo-cecal valve. The bowel is detubularized and configurated in a cylinder. Then the neobladder is anatomized to the urethra and ureters. From 1989 to 1995 20 patients underwent ileal orthotopic urinary diversion according to Hautmann. Two patients died, the others are still disease free (mean follow up 36 months). The high capacity and low pressure allow a good continence control, while among metabolic alterations the most frequent is metabolic acidosis. The ileal neobladder represents a valid alternative to any form of cutaneous urinary diversion and is associated to a low incidence of complications.