Intestinal ischemia should be suspected in any patient following aortic surgery who has pain out of keeping with the operation, postoperative diarrhea (with or without bleeding) or an unexplained metabolic acidosis. Ten such cases of intestinal ischemia were identified during a 10-year period at the Toronto General and Toronto Western hospitals. Six occurred following repair of a ruptured abdominal aneurysm, one followed elective aneurysmectomy and three followed elective bypass for occlusive disease. The overall mortality was 70%. Transmural bowel infarction was found in six patients (all died), while four patients had partial-thickness injury (one died, three had late strictures). Potentially preventable factors in each patient, either single or multiple, were identified and are discussed. Emphasis on early diagnosis is stressed, because once transmural necrosis has occurred the prognosis is poor.