Primary carcinoma of the bile ducts is an uncommon lesion that is difficult to diagnosis in early stage. Correct diagnosis with determination of site and extent of the carcinoma is essential for proper management. Authors presented 35 cases of bile duct carcinoma, confirmed at Seoul National University Hospital from 1978 to 1981, and analyzed their clinical and radiological findings. The results were as follows: 1. The 6th decade was the predilection age, and the ratio of male to female was 4:3. 2. The locations of bile duct carcinomas were common bile duct in 31%, porta hepatis in 26%, junction in 17%, diffuse involvement in 17%, and common hepatic duct in 9% in order of frequency. 3. Ultrasonography was done in 31 cases. Dilatation of intrahepatic ducts was noticed in 28 cases. Among the 28 cases, correct diagnosis as bile duct carcinoma were made in 5 cases. Proximal obstructive patterns were observed in 14 cases and distal obstructive patterns in 9 cases. 4. ERCP was done in 15 cases. Successful studies of ERCP were done in 8 cases of them. Among the cases, diagnosis as bile duct carcinoma were made in 4 cases. 5. PTC was done in 20 cases and successful in all of them. Correct diagnosis as bile duct carcinoma were made in 16 cases and the diagnostic accuracy was 80%.