Peripheral cholangiocarcinoma arises from the small bile ducts and presents with an infiltrative growth, but intraductal growth in the peripheral large duct tributaries is an extremely unusual manifestation, especially in cases with Clonorchis sinensis infection. A case of surgically resected intraductal variant of peripheral cholangiocarcinoma of the liver in a 46-year-old Korean man who had eaten raw fresh-water fish is described. The tumors were entirely confined within the dilated peripheral tributaries of the left intrahepatic bile duct, and no tumorous extension beyond the bile duct walls into the hepatic parenchyma or to the hilum was found. Microscopically, the tumor was a well-differentiated papillary adenocarcinoma of large duct origin, and the major branches were plugged with multiple tumor casts. A histologic feature of a C. sinensis infection with fully developed adenomatous hyperplasia was associated in the peripheral septal ducts, and the nonneoplastic large duct showed focal epithelial dysplasia. The authors assume that intraductal cholangiocarcinoma is a distinct macroscopic subtype, and that a C. sinensis infection may also be responsible for its development.