The artificial urinary sphincter AS800 was implanted in 33 male and 13 female patients with congenital urinary tract incontinence. In 15 patients (32 per cent) previous operations to correct incontinence had failed. The sphincter was implanted around the bladder neck in 43 patients and around the bulbous urethra in 3. Mean patient age at the time of sphincter implantation was 13 years. In 40 patients (87 per cent) the sphincter functions well after a mean followup of 25 months and 39 patients (85 per cent) have satisfactory continence. In 6 patients the sphincter was removed because urethral, vulvar or scrotal erosions developed, all of whom had had previous surgical procedures in the area of the erosion. In 1 patient not operated upon previously erosion of the bulbous urethra developed. He did well after a new sphincter was implanted around the bladder neck. Five patients required an enterocystoplasty to achieve continence following the sphincter implantation. Nine patients required surgical revision of the sphincter for mechanical failure, technical errors, trauma and patient growth. We conclude that in patients with neurogenic sphincter failure implantation of an artificial sphincter around the bladder neck should be considered as the initial treatment of choice.