From July 1989 to June 1999, 100 patients, 76 male and 24 female, were admitted for treatment of hepatocellular carcinoma (HCC) with transcatheter oily chemoembolization (TOCE) using lipiodol 10 ml mixed with an anticancer drug (mitomycin C 20 ml) and gelfoam particles, described by Nakamura H et al. The periodic follow-up angiogram showed hepatic collaterals which developed according to the mode of embolization. For peripheral hepatic arterial embolization such as segmental or lobar arterial embolization, the intrahepatic collaterals were commonly demonstrated. However, for more proximal hepatic arterial embolization of the tumor feeder arteries such as the proper hepatic artery and the common hepatic artery, the extrahepatic collaterals were commonly demonstrated with fine, small tortuous vasculatures, rendering a repeat TOCE more difficult. The hepatic collaterals are presented.