During a five-year period, 82 patients were treated for acute pancreatitis, 63 of whom were proved to have associated biliary tract disease. In 18 of the 63, the accepted preoperative diagnostic measures failed to demonstrate pathologic findings in the biliary system. In 16 of the 18 patients, stones were discovered at the time of operation, although in five they were so small as to be demonstrable only filtering the aspirated bile through gauze. In the two of the 18 without stones, cholecystitis was present. In 14 patients the ducts choledochus and the pancreatic duct had a common path. All patients had no further pancreatitis two to eight years cholecystectomy. In Israel, where alcoholism is rare, three fourths of the cases of acute pancreatitis are associated with gallbladder disease.