Endoscopic retrograde cholangiopancreatography(ERCP) wasperformed preoperatively on 29 patients suffering from hepatocellular carcinoma (HCC) invading bile ducts .The outstanding features were: 1.Most of the filling defects were situated within the common , right or left hepatic duct associated with proximal bile duct dilatations(17 cases); 2.Tumor encasement resulted in localised or diffused irregular strictures and dilatations (9 cases); 3.Displacement and stretching of the intrahepatic ducts by pressure of tumor mass(3 cases) .These features are different from that in cholangiocarcinoma.ERCP should be considered as an important diagnostic procedure for HCC.It is especially useful for cases with obscure intrahepatic duct dialatation and /or an increase of AFP, and will help early diagnosis of HCC.