The spectrum of clinical severity of acute pancreatitis varies widely, but the most important is to predict high risk patients, so that, a number of classification systems have been proposed with the main focus is on laboratory findings.The purpose of this paper was to validate the Rabeneck Clinical prognostic staging system (using clinical features and comorbid illness) which classified in three stages: I, II and III. We conducted a retrospective study in 51 patients admitted to Hospital Arzobispo Loayza, from 1988 to 1994. 42 (82.4%) were female and 9 (17.6%) male. The average age was 40.3 years. The range hospital stay was 3 to 41 days. Ultrasonographically we found some alterations in pancreas texture about 84.4% and gallbladder stones in 57.7%. The mortality rates according to Rabeneck system were stage I: O of 44 (0%); stage II: 1 of 4 (25%); stage III 2 of 3 (66.7%) In conclusion the new prognostic staging system is easy to use, simple and require no additional laboratory test, so that utility to our institutional situation.