Percutaneous Tranthepatic Cholangiography (P.T.C.) is the most valuable diagnostic technique to differentiate surgical jaundice from hepatocellular jaundice and to search the cause of the obstructive jaundice. P.T.C. using 23G Chiba needle has a high success rate in not only surgical jaundice cases but also medical problems of the liver and has a low risk. Authors present the clinical and P.T.C. findings of 189 cases which were experienced in last 5 years, from July 1973 to August 1978, at the Department of Radiology. Seoul National University Hospital. The summerized results were as follows: 1. Among the 189 cases, male was 133 cases and female was 56 cases, and the male to female sex ratio was 2 : 1. 2. The most frequent P.T.C. diagnosis was common bile duct stone (55 cases), and common bile duct cancer (54), pancreatic cancer (33), Cancer of Ampulla Vater (7), sclerosing cholangitis (5), clonorchiasis (4), gall bladder cancer (3), gall bladder stone (3), metastasis (3), hep toma (3), C.B.D. stone, other (5), and normal (14), in decreasing order. The sum of three main diseases, C.B.D. stone, other (5), and normal (14), in decreasing order. The sum of three main diseases, C.B.D. cancer and pancreatic cancer, was 75% of all cases. 3. The overall success rate of P.T.C. was 92.6%, and the diagnostic accuracy of P.T.C. was 86.9%. 4. Confirmed 19 cases of misdiagnosis was including 5 cases of gall bladder cancer, 4 of pancreatic cancer, 3 of common bile duct cancer, 2 of common bile duct stone, and others 5. All 4 cases of pancreatic cancer was misdiagnosed as common bile duct cancer. 5. Barium swallowing after P.T.C. was very useful in differential diagnosis of obstructive jaundice giving informations such as relative position of stomach, position of Ampulla Vater and the distance from Ampulla Vater to the obstruction site. 6. major complication such as hemoperitoneum, bile peritonitis, septicemia and severe hypotension was occurred in 6.5% of all P.T.C. case . 7. P.T.C. using fine Chiba needle was a very useful and informative diagnostic procedure in differential diagnosis of obstructive jaundice from hepatocellular jaundice and the nature of obstructive lesions.