A 60-years old man was admitted for RUQ pain since 10 days before. He was found to have jaundice(total bilirubin; 7.7mg%) and confirmed as a giant common bile duct stone and multiple gall bladder stones by P.T.C. The mechanisms of common bile duct stone formation are followings; First, forceful expulsion as the gall bladder contracts. Second, relaxation of the cystic duct. Third, displaced from the gall bladder by erosion into the common bile duct. Fourth, left behind in the cystic duct remnant after cholecystectomy may migrate with the common bile duct stone. The cholecystectomy was performed and the giant common bile duct stone removed after the duodenostomy. During operation, we found a giant common bile duct stone which was escaped from common bile duct and dilatation of fistula opening. (about 3 cm). This report represents one of the largest common bile duct stones in previous reports.