Nonocclusive intestinal infarction (NOII) is described as bowel necrosis at celiotomy or autopsy without evidence of thromboembolism, vasculitis, or mechanical obstruction. The mortality for this entity is as high as 90 per cent in some series. From January 1990 to January 1995, we identified 15 patients who met the criteria for NOII identified at celiotomy or autopsy. We collected data on demographics, comorbidities, presenting signs and symptoms, laboratory workup, time to definitive therapy, and outcome. Our goal was to improve our ability to identify and treat this devastating surgical problem. There was a 4.5:1 female to male ratio, and patients had an average age of 73 +/- 10 years. Significant comorbidities included coronary artery disease (87%) and atrial fibrillation (73%). Eleven patients were diagnosed at celiotomy and four at autopsy. Overall mortality was 67 per cent. The most common presenting symptoms were abdominal pain (93%) and distention (80%) and mental status changes (60%). Peritonitis was less common, present in only 40 per cent of the patients. Leukocytosis, bandemia, increased creatinine, metabolic acidosis, and hypoxemia were common among all patients. There was a significant difference in time to definitive therapy in survivors versus nonsurvivors (1.2 +/- 0.89 vs 4.8 +/- 2.0 days; P < 0.02, t test). These data suggest that NOII is a lethal surgical problem. A history of coronary artery disease and atrial fibrillation was common among all patients. Various nonspecific presenting signs, symptoms, and laboratory values are suggestive of this diagnosis. A high index of suspicion in select patients and early intervention may lead to improved outcome.