Background/Aims: Although the incidence of intrahepatic biliary stone in Korea is relatively high, the pathogenetic role of intrahepatic biliary ]esion on the genesis of intrahepatic stone is not clearly understood yet. This study was perfomed to investigate the patbological changes of intrahepatic bile ducts in hepatolithiasis and compare with other reports, thus get some information about the pathophysiologic role of those lesions. Methods: Patho]ogical and histochemical studies were done on 43 cases of liver resected for the treatment of intrahepatic biliary stones during last 16 years. Results: The highest incidence was at the 6th decade. Male to female ratio was 1:1.4 (18cases to 25 cases) and mean age was 45.4 years. More than half of the cases complained less than 2 months of biliary symptom duration. Majority of the cases(38 cases, 88.3%) revealed stones in the left intrahepatic bile ducts. Histological changes of the intrahepatic bile ducts harboring biliary stones showed superficial epithelial hyperplasia in 20 cases(46.5%), proliferation of intramural glands in 36 (83.7%), extramural glandular hyperplasia in 42(97.7%), pseudopyloric glands in 3(7.0%)and pancreatic acinus in 3 cases(7.0%), and chronic inflammatory reaction in all the cases examined. Mucin in the pseudopyloric glands were mixture of class m mucin and sialo- and sulphomucin. Conclusions: It is concluded that histologic lesions associated with the intrahepatic biliary stones were chronic inflammatory reaction and proliferation of intrahepatic ductal epithelium and peribiliary glands secondary to the inflammation. Hypersecreted glandular secretion of peribiliary glands can be an augumenting factor of the increment of the biliary stones. (Korean J Gastroenterol 1996; 28: 697 - 704)