Knowledge of the junction of the cystic and common hepatic duct is essential for endoscopic management of biliary tract disease. The cystic and common hepatic ducts were evaluated retrospectively in cholangiograms obtained for a variety of indications in 524 persons. The cysticohepatic junction was adequately visualized in 70%. Medial junctions were noted in 18% and a spiral configuration in 32%, both more common than reported. An 11% occurrence of parallel duct systems was less frequent than expected. In 10% of patients, the cystic duct entered the hepatic duct in the distal third of the extrahepatic biliary tree. The importance of understanding this anatomy is illustrated with selected cases of therapeutic biliary endoscopy and laparoscopic cholecystectomy complications. Suggestions are made for improving performance in this area.