BACKGROUND: Studies on the incidence and etiology of acute pancreatitis show large regional differences. This study was performed to establish incidence, etiology and severity of acute pancreatitis in the population of Bergen, Norway. METHODS: A study of all patients with acute pancreatitis admitted to Haukeland University Hospital over a 10-year period was performed. Information was obtained about the number of patients with acute pancreatitis admitted to the Deaconess Hospital in Bergen. RESULTS: A total of 978 admissions of acute pancreatitis were recorded in these two hospitals giving an incidence of 30.6 per 100,000. Haukeland University Hospital had 757 admissions of acute pancreatitis in 487 patients. Pancreatitis was severe in 20% (96/487) of patients, more often in males (25%) than in females (14%). Mortality due to acute pancreatitis was 3% (16/487). Gallstones were found to be an etiological factor in 48.5% and alcohol consumption in 19% of patients. The risk of recurrent pancreatitis was 47% in alcohol induced and 17% in gallstone induced pancreatitis. The last five years of the study period, endoscopic sphincterotomy of patients with gallstone pancreatitis, resulted in drop in relapse rate from 33% to 1.6%. CONCLUSION: The incidence of acute pancreatitis was found to be 30.6 per 100,000 with 48.5% associated with gallstones and 17% alcohol induced. Incidence of first attack was 20/100,000. Pancreatitis was classified as severe in 20% of cases with a mortality of 3%.