Between the years 1975 and 1984, 228 patients with acute pancreatitis (A.P.) have been studied at the "A. Posadas Hospital". The diagnosis was confirmed in 212 patients by surgery, in the remaining 16 by clinical evaluation, increase in the activity of serum or peritoneal fluid amylase, ultra-sonography and computed tomography. The sex distribution was: female 151 (66.2%) male 77 (33.8%), the mean age in each group was 42.9 and 45 years respectively. The etiologic factors were: biliary tract disease 178 (78%) alcohol 24 (10.5%) idiopathic 16 (7%) others factors 10 (4.4%). We found mild and moderate forms of the illness in 179 (78.5%) and severe form in 49 (21.5%) patients. The mortality rate of the whole group was 29 (12.7%) and according to the etiology it was, in the biliary group 20 (11.2%) alcoholic 4 (16.6%) idiopathic 3 (18.7%). The mortality in the mild and moderate forms was 5% and 40.8% in the severe forms. The patients who underwent surgery were classified in three groups according to the opportunity of surgical treatment: elective surgery, early surgery, surgery for complications. There was no mortality in the elective surgery group. The patients operated on early period had a mortality of 18.75% (21 pts.) whereas those operated due to complications had a mortality of 42.1% (8 pts.). According to the above mentioned experience we consider that a patient with an A.P. must be classified with the known indexes in mild or severe forms, at the same time one should study the actual etiologic factor.(ABSTRACT TRUNCATED AT 250 WORDS)