A multicenter study of acute necrotizing pancreatitis (ANP) classified in accordance with the Balthazar criteria (grades D and E), has been performed in 12 teaching hospitals. A total of 233 patients were reviewed, and the mortality rate was 26.6%. The most common etiology was biliary pancreatitis (45.5%). Among the complications, shock, renal insufficiency, pulmonary insufficiency and hemorrhagic gastritis were associated with a mortality rate of 51-66%. Diffuse fluid collections were associated with a higher mortality rate (26.8%) than localized fluid collections (14.5%). In 106 patients with gallstone pancreatitis, early surgery was performed in 17, and 5 patients (29.4%) died. No mortality was observed in 32 patients with delayed surgery. Sphincterotomy was performed in 13 patients, and 4 (30.7%) died. Early surgery (necrosectomy and closed peritoneal lavage) was undertaken in 75 patients, with a mortality rate of 39%. In conclusion, the morbidity and mortality rates of ANP can be improved with proper monitoring, adequate supportive care and the judicious use of surgery based on clinical and morphological findings.