The authors' experience with right-sided diverticulitis is reviewed. The symptoms among 18 patients were continuous right lower quadrant abdominal pain and periumbilical pain radiating to the right lower quadrant. Only three patients had nausea and vomiting. Twelve patients (67 per cent) had an abnormally high white blood cell count; three had granulocytosis. Barium enema examination was not a helpful diagnostic aid; and in only two patients was the preoperative diagnosis correct. The operative procedures undertaken were right colectomy with ileotransverse colostomy (15 patients), partial right colectomy with ileoascending colostomy (two patients), and diverticulectomy and appendectomy (one patient). There were no deaths; the average hospital stay was 14.2 days (range 5 to 30 days). The authors conclude that there is no characteristic clinical pattern pointing to this diagnosis; diagnostic maneuvers are usually unrewarding; right hemicolectomy is a safe and expeditious procedure; and open cecotomy is not favored, as recommended in the medical literature, to establish the diagnosis.