PURPOSE: To determine the radiologic characteristics of the hepatocellular carcinoma with intrabile ducttumor growth and extension. MATERIALS AND METHODS: We analyzed the arterial-dominant phase(ADP) CT scans, hepaticangiograms and cholangiograms in nine cases of hepatocellular carcinomas with intrabile duct tumor growth andextension confirmed by tumor thrombectomy. RESULTS: The gross types were nodular in three cases and massive infive. Two masses were larger than 6cm, four were between 3 and 6cm, and three were less than 3cm. Among six casesof ADP-CT scan, dense contrast enhancement was observed in four, minimal enhancement in one, and no enhancement inone. In one case we were unable to find a primary mass. With regard to tumor staining on hepatic arteriograms, five cases were hypervascular, one case was hypovascular, and the remaing one was not found. All tumor thrombi were seen as filling defects which were dilating the bile duct on cholangiograms. Among five intrabile ducttumors, thrombi were detected on ADP-CT scan(n=6), dense contrast enhancement was observed in one case, minimalenhancement in two cases and no enhancement in two cases. CONCLUSION: Intrabile duct tumor growth and extensionin hepatocellular carcinoma(HCC) does not correlate with location, mass size or tumor vascularity. It was concluded that tumor thrombi were formed through the direct invasion by a tumor of a branch of the intrahepaticduct, its growth in the distal direction in the biliary tree and subsequent extension to the common bile duct. Thrombi were more hypovascular than primary mass.