Peritonitis is the most common complication of chronic ambulatory peritoneal dialysis (CAPD). It is often a diagnostic challenge to differentiate those patients with CAPD-associated infections from those who have unrelated gastrointestinal pathology as the cause of peritonitis and would benefit from surgical exploration. A retrospective chart review was performed on all patients at a single institution who were on CAPD between the years 1990 and 1998 and who underwent laparotomy for peritonitis. Six patients underwent laparotomy. Four were male and two were female; ages ranged from 34 to 80 years. Perforated appendicitis was the cause of peritonitis in three patients, perforated diverticulitis was present in two, and one was without any suppurative intra-abdominal process. In each case CT scan of the abdomen was nondiagnostic. There was a delay in diagnosis of 10 days (range 3-21 days) and an operative mortality of 16 per cent.