Sixteen patients having undergone ureterosigmoidostomy have been examined using fiberoptic coloscopes. Morphology and function of both the colonic mucosa and the ureteral stumps have been evaluated by direct observation, biopsy brush cytology and i.v. injection of methylen blue. The obtained encouraging results point to this fiberendoscopic diagnostic approach as an easy and useful follow-up examination of patients with intestinal urinary diversions.