In a consecutive series of 310 cholecystectomies performed for gallstones, dissection of the operative area disclosed 75 patients (24%) who had 84 potential anatomic hazards which could have led to a bile duct injury. There were 49 hazards related to the arterial supply, 8 to the position of the Hartmann pouch, and 27 were related to the anatomic features of the cystic duct or of the other extahepatic bile ducts. The practical significance of these hazards in terms of prevention of bile duct injury during cholecystectomy is discussed.