INTRODUCTION Suspicion of intestinal necrosis in patients with mesenteric ischemia is mandatory in surgery. Many patients develop massive necrosis after open surgery. However, in some frail, elderly patients, preoperative prediction of massive intestinal necrosis could avoid an unnecessary laparotomy. The aim of this study was to assess predictive factors of massive intestinal necrosis in acute mesenteric ischemia. PATIENTS AND METHOD We retrospectively evaluated a consecutive sample of 155 patients, 88 men and 67 women, with a mean age of 71.9 years (SD +/- 13.6), who underwent surgery for acute mesenteric ischemia in our institution from 1990 to 2004. Age, sex, clinical features, laboratory findings, and delay to surgery were recorded and assessed as possible risk factors for massive intestinal necrosis. A logistic regression model was used to identify independent prognostic factors. RESULTS Of the 155 patients, massive intestinal necrosis was recorded in 48 (31%; 95% CI: 23.4-38.6). A statistically significant association was found between massive intestinal necrosis and age (p = 0.04), previous digoxin use (p = 0.01), shock (p = 0.009), hemoconcentration (hemoglobin levels > 16 g/dL) (p = 0.02), hyperamylasemia (p < 0.001), acidosis (p = 0.012), and alkalosis (p = 0.048). Multiple stepwise logistic regression analysis identified three independent prognostic factors that were significantly associated with a higher risk of massive intestinal necrosis: shock (OR = 3.4; 95% CI: 1.1-10), hemoconcentration (OR = 6; 95% CI: 1.6-22.8), and hyperamylasemia (OR = 4.2; 95% CI: 1.5-12.2). CONCLUSIONS Massive intestinal necrosis can be observed in at least 25% of patients undergoing surgery for acute mesenteric ischemia. Within the limitations of a retrospective study, the variables of shock, hemoconcentration and elevated serum amylase levels may be considered as independent predictive factors of fatal necrosis of the bowel.