A 22-year review of 328 patients with Crohn's disease revealed 70 patients with urinary tract symptoms. Cystitis was the most common problem, occurring in 44 patients. The urinary tract infections were recurrent in most patients, usually with 3 or 4 attacks per year. Despite the persistence of urinary infection, only 3 patients developed chronic pyelonephritis. Forty-nine patients had intravenous urography, and many were found to have slight dilatation of the upper urinary tract on one side. Seven patients had hydronephrosis, 3 with pyonephrosis. Five of 6 patients who developed calculi had a bowel resection. All of the recovered calculi were oxalate stones, but 3 were passed spontaneously and not analyzed. Eight patients, 7 of them males, had an ileovesical fistula. In 1, the colon was also affected. It was unusual for these patients to have severe urinary symptoms. One patient had a fistula from the rectum to the urethra. Although 32 of the 70 patients were female, most of the severe complications occurred in men. Aggressive investigation is not indicated, nor is radical surgery required.