A retrospective study was carried out in patients who had operative procedures for biliary tract stone for the purose evaluating efficacy of operative cholangiogram. One 220 consecutive charts were reviewed in patients who had been admitted with diagnosis of biliary tract stone to Guro Hospital.Korea University, College Medicine for a period of 3 years and 4 months starting from September 1983 to December 1986. Among these 220, 146 patients who had operative procedure were elected for this analysis. Intraoperative cholangiography was performed in 83 patients of whom 21 patients had cystic duct cholagiography and 62 patients had T-tube cholagiography: The incidence of common duct stones on intraoperative cholagiography was 5%. The incidence of residual stones was 8.7% on postoperative T-tube cholangiography: With such high incidence of unsuspected common duct stone and residual stone, intraoperative cholangiogram including cystic duct cholangiogram are worth procedure for biliary tract stone.