There are the best diagnostic results by endoscopic examination of the common bile duct. Both rigid and flexible instruments can be used for the examination. The advantages and disadvantages will be discussed. The stump of the cystic dust will be useful to clarify pathological finding by x-ray in the distal bile duct. Usually, however, the instrument is introduced by means of a choledochotomy. In the last 16 years in 1023 cases the bile duct were examined endoscopically, 330 via the cystic duct, 693 via a choledochotomy. Stones were detected in 541 cases (52.9%), in 16 cases (2.9%) a stone was overlooked. Severe complications by operative choledochoscopy were not seen.