CT scan is widely used in the evaluation of hepatobiliary system and contrast study is generally performedwith non-biliary contrast media. Therefore the normal intrahepatic bile ducts are not readily visible and alsoextrahepatic bile ducts are occasinally not discriminated from adjacent structures, in spite of improvedresolution of the CT scanner. This study was performed to evaluate the usefulness of cholangiographic enhancementin biliary CT examination. In the control group (n=5), we measured the CT number of the peripheral hepatic duct,perioportal duct, common bile duct and gall bladder, respectively, at the interval of 30 minutes upto 2 hoursafter intervenous infusion of biliscopin(30ml) and observed time-denstiy relationship of infused biliscopin in thebiliary system. In the patient group (n=23), we observed visualization rate of the bilary system and serumbilirubin level at 30 minutes after infusion of biliscopin(30ml). The results were as follows: 1. The peak densityoccurred at 30 minutes after infusion of biliscopin. 2. Visualization rate was 100% in normal bilirubin groupwhereas it was 91.7% in abnormal bilirubin group. 3. The cholangiographic enhancement of biliary CT scan is usefulin the evaluation of intra-and extraheptaic biliary system.