BACKGROUND The factors associated with outcome of patients with nonocclusive mesenteric ischemia are poorly defined. METHODS Over a 7-year period, 34 consecutive patients with nonocclusive mesenteric ischemia were identified. RESULTS The mean age of the study patients was 63 years (range 31 to 94); 21 of 34 (62%) were men. The mean delay in diagnosis was 31 hours (range 7 hours to 6 days). Seven of 34 (21%) underwent preoperative visceral arteriography. Two of these 7 required surgery, and both died as a result of intestinal infarction. The remaining 27 had the diagnosis made at celiotomy. Among the 29 who were explored, 16 of 29 (55%) had intestinal infarction. Twenty-one of 29 (72%) had segmental bowel injury whereas 8 of 29 (28%) had massive injury. Among those with segmental infarction, primary anastomosis was performed in 12 of 21 patients (57%); 5 of the 12 (42%) died. Nine of 21 patients (43%) underwent delayed anastomosis; 2 of the 9 (22%) died. No patient with massive injury underwent primary anastomosis. Second-look laparotomy was performed on 22 of 29 (76%). Eleven of those 22 (50%) had a further bowel resection. Overall, 16 of 29 (55%) who underwent surgery for nonocclusive mesenteric ischemia are alive. CONCLUSIONS Improved survival from nonocclusive mesenteric ischemia is dependent upon the identification of high-risk groups, aggressive reexploration, and delayed intestinal anastomosis.