The most common aetiological factors of acute pancreatitis in an unselected group of 215 consecutive surgical patients were biliary tract disease (40.0%), alcoholism (20.0%) and gastroduodenal ulcer (4.2%). In women, biliary tract disease was by far the most common cause (61.3%), but in men considerably high frequencies of alcoholism (48.3%) and gastroduodenal ulcer (15.7%) were noted as at least one possible aetiological factor. This deserves a special notation when contemplating prophylactic measures to prevent recurrences of acute pancreatitis.