The Radiological analysis in normal and variations of hepatic duct system were performed on the 154 cases of surgically explored biliary disease patients from Jan. 1973 to Dec. 1977 for 5 years at Yonsei University Hospoital. The analytic results are as follows; 1. In T-tube cholangiogram, normal variations, of intrahepaticduct by OHTO classification, the most common type was type I(66.3%) and type II(7.8%), type III(1.3%), typeIV(7.8%), typeV(10.4%) and other type (6.4%). 2. The highest incidence of age group was 41-50 years(27%), yet morethan 75% cases were belong to the group after third decade. According to sex incidence, the female was slightly prevalent than male. 3. The causative diseases of 154 analyzed cases are, disease of calculus, 118 cases, congenital anomalies; 6 cases, neoplams of biliary system: 6 cases, and parasitic diseases; 19 cases. 5. Among 118 cases of biliary diseases associated with biliary duct stones, intrahepatic duct stones were about 5 percent and left intrahepatic stones were prevalent than right intrahepatic stones. 6. In oral or I.V. Cholangiogram prior toopeation (87 cases from 154 cases), of each nonvisualization of gall bladder and CBD was 37 cases and 27 cases ,were well visualized in gall bladder and CBD was 18 cases, and gall bladder and CBD stones were detectable in 18cases. 7. In T-tube cholangiogram, the prominent findings were dilated biliary tree, normal biliary tree, cholangitic pattern, and residual stones in the intrahepatic and CBD in order of frequency.