The authors report their experience with 88 cases of psoas bladder in children and in adults. The essential indications have been failure of previous ureterovesical implantation, certain megalo-ureters, tuberculous stenosis, and pelvic fibrosis in adults. In 32 operations on children there was only a single case of stenosis, but six cases of residual reflux all linked to a too short submucous passage. In the 56 operations in adults there were four ureteral stenoses. Note the almost constant good results in children operated for the first time, and in adults operated for tuberculosis. The authors stress several points: - the psoas bladder is the first type or reparative surgery to consider when one is confronted with loss of substance of the ilio-pelvic ureter; - in reparative surgery of the terminal ureter, the psoas bladder is indicated each time it is not possible to prevent reflux by simple advancement of the ureter submucously. The psoas bladder seems to the authors to be an advantageous alternative to the Leadbetter-Politano operation; - the need to amply dissect the dome of the bladder and, if necessary, the lateral aspects of the bladder, the ureter, even the kidney and the renal pedicle in difficult repairs when there is extensive loss of tissue; - the obligation to renounce this technique whenever the dissection pushed to the limit does not allow an anastomosis without tension.