Authors used the Mainz pouch II technique for urinary diversion in 40 patients suffering from bladder cancer. They made minor modifications to the original surgical technique: a longer, 40 cm bowel is detubularized, the ureters are pulled through the mesosigma and embedded in a groove of the bowel's mucosa, the sigma pouch is fixed to the dorsal peritoneum, a straight suture is used. Single-row on the dorsal wall and two-rows on the ventral wall. Within a few days after the surgery suture insufficiency occurred in the abdominal wall in 5 cases, in the bowel in 2 cases. To treat suture disrupture of the bowel authors transformed the pouch, added a newly detubularized bowel segment to create a spheric rectum pouch and performed a definitive colostomy. During the follow-up period of six months to four years 8 of the 40 patients died from bladder cancer, 2 from cardiac failure, 1 from pulmonary embolism, and 6 have had a recurrence of the tumor. In the 23 tumor free patients we found no reflux, one has a slight stenosis of the ureter, febrile pyelonephritis did not occur, the pouch did not slip, the ureter had no kinking, and all patients are continent. Hyper-chloraemic acidosis has been prevented by regular administration of sodium bicarbonate or kalium citrate. Authors believe that Mainz pouch II is to be the most appropriate continent urinary diversion if an orthotopic substitution is not possible.