Seventy-eight cases of severe acute pancreatitis were admitted to Mie University and its affiliated hospitals. These were subdivided into Group I (1976-1983) and Group II (1984-1989). The rate of early death was 34.8% in Group I and 9.3% in Group II. Among operated cases, peritoneal drainage alone was not effective with the worst mortality rate of 47.1%, especially in gallstone pancreatitis, with a 100% mortality rate. Early detection of infected necrosis or abscess using enhanced CT and subsequent drainage should be performed in cases of severe acute pancreatitis. A total 1182 cases of severe acute pancreatitis out of 12,309 cases of acute pancreatitis were collected in Japan by Saito et al., who belong to the Research Committee of Intractable Diseases of the Pancreas supported by the Japanese Ministry of Health and Welfare. Furthermore, 473 cases of severe acute pancreatitis in the Japanese literature reported from 1987 to 1990 were reviewed. Then, surgical indications and procedures were discussed. The incidence of necrosectomy has been increased to 10.3% from 3%, and biliary drainage procedure increased for severe acute pancreatitis. Indication of necrosectomy with or without open drainage method should be carefully evaluated in each institution.