Nonocclusive mesenteric infarction has recently been diagnosed with increasing frequency in dialysis patients. Although most reports have concerned patients on hemodialysis, the condition has also been reported to occur in patients on continuous ambulatory peritoneal dialysis. This report describes such a case developing in a woman whose end-stage renal failure was due to adult polycystic kidney disease. Associated predisposing factors were the presence of orthostatic hypoxemia, postural hypotension and extensive atheromatous changes of the abdominal aorta. In keeping with the known difficulty of establishing the diagnosis of mesenteric ischemia, the diagnosis in our patient was also delayed. She was initially thought to suffer from an episode of peritonitis and/or colonic perforation secondary to the performance of a cleansing enema. Only upon showing pneumatosis coli of the right colon on abdominal computerized tomography was the correct diagnosis made. Laparotomy revealed extensive necrosis of the ascending and transverse colon. A total colectomy and ileorectal anastomosis were performed. The patient died on the 17th day following surgery. This case serves to illustrate that mesenteric infarction should be considered in predisposed patients on continuous ambulatory peritoneal dialysis. The presence of peritonitis may mask the underlying pathology and waylay the unwary physician.