Direct visualization of the biliary tree using flexible fiberoptic choledochoscope has been recommended as a technique to improve the accuracy of common bile duct exploration and to extract the postoperative retained stones. In several series. the incidence of retained stone has dramatically decreased after using the choledochoscope. Recently, there is increasing tendency to depend upon chnoledochoscope for removal of retained or recurrent biliary tract stones. Moss, Birkett, and Yamakawa reported removal of a retained stone using a choledcochoscope passed through the T-tube tract. At the department of Surgery, Wonju MIedical College, Yonsei University, authors report successful extraction of retained stones in 15 patients between February 1983 and August 1984 with flexible fiberoptic choledochoscope passed through the T-tube tract. In using the choledochoscope, we concluded that the major factors for successful extraction of retained stones are the diameter and the location of the T-tube tract. There were no significant complications after postoperative choledochoscopy. Therefore, it is strougly recomended choledochoscopic removal of retained stone is the approach of choice before reoperation.