Between 1976 and 1994, 318 patients underwent surgical closed retro-endoperitoneal drainage and post-operative lavage for acute necrotizing severe pancreatitis. The main indication was sepsis (66.4%). The ratio between operated on and the overall number of observed patients has been progressively shifting towards medical treatment. Furthermore in the operated group the timing of surgery has been delayed step by step. The Authors discuss improvements in the understanding of the etiological and therapeutical aspects of the disease which has had a better outcome in recent years, survival rate of 91.4%. The personal option for the closed surgical approach is based on the progressive improvement of the technique and on the good results obtained both in terms of mortality and associated morbidity; as regards the latter problem the open techniques seems to be related to a higher complication rate than the closed one.