Although ultrasonography replaced many invasive studies in biliary tract diseases, direct cholangiography does still play an important role in the diagnosis and management of choledocholithiasis. Endoscopic retrograde cholangiography (ERC) is regarded as the best method in evaluation of exact extent of the disease and its frequent complication, cholangitis. Authors analysed 56 cases of choledocolithiasis diagnosed by ERC and compared these with ERC in 18 cases of normal, 22 cases of cholecystitis, 15 cases of clonorchiasis and 9 cases of parenchymal diseases of liver. The results are as follows: 1. ERC findings of choledocholithiasis are filling defects by stone or stones, dilation of common hepatic as well as common bile ducts and findings of cholangitis. 2. ERC findings of cholangitis are dilatation of larger intrahepatic biliary radicles and acute peripheral tapering, decrease of arborization, increased or right angle branching pattern, straightening and rigidity as well as irregular narrowing of intrahepatic biliary trees. This findings are observed in majority of choledocholithiasis. 3. Over 9mm in diameter at intraprancreatic portion of common bile duct was regarded as abnormal, with 95% sensitivity, 85% specificity and 91% diagnostic accuracy by decision matrix analysis. and 91% diagnostic accuracy by decision matrix analysis. 4. In the presence of dilatation of CBD and findings of cholangitis in ERC, one should consider choledocholithiasis in spite of absence of stone defect.