We reviewed 15 patients who underwent 16 ureterosigmoidostomies from 1975 to 1989. The underlying disease was bladder exstrophy in 13 patients. Urinary diversions have been performed according to Mathisen in 15 patients, one reoperation has been performed according to Coffey. Standard post-operative controls consist of physical examinations, capillary blood gas samples, intravenous pyelograms, inulin clearance measurements, 123I-hippuran scintigraphies and colonoscopies. Results concerning continence are judged very satisfactory in 80% of patients. 34% of patients presented with one or more episodes of unilateral or bilateral pyelonephritis. Intravenous pyelograms showed improved or unchanged urinary tract dilatation in 45% of kidneys and moderate and severe dilatation in 55%. Inulin clearance remained in normal range in 4 out of 6 patients followed. Renal function assessed by means of renal scintigraphy remained unchanged in 61% of kidneys, slightly decreased in 22% and severely in 17%. All patients are kept on a sodium-citrate therapy. Only one patient shows growth disturbances. Out of 9 patients followed with colonoscopy, none showed signs of malignancy.