OBJECTIVE We evaluated ureterorenoscopy as a treatment approach to symptomatic caliceal diverticula. METHODS Since 1989, 20 women and 6 men suffering from pain, recurrent urinary tract infections or urosepsis were treated using flexible ureterorenoscopy, balloon dilation or incision of the diverticular neck and subsequent intrarenal stone fragmentation when needed. RESULTS Of 19 upper and middle caliceal diverticula 16 (84%) and 2 of 7 lower caliceal diverticula were successfully identified. The orifice to the diverticular cavity was dilated and the stone was fragmented. Of the patients 13 were treated as outpatients and 10 required a 1-night hospital stay. Of those patients in whom the diverticulum could be entered and the stone fragmented 100% were symptom-free at a mean followup of 39 months. One patient required repeat treatment to remove residual stone. CONCLUSIONS Ureterorenoscopy produces minimal morbidity and is an effective treatment of upper and middle caliceal diverticula.