Transcatheter arterial embolization (TAE) was performed in 97 patients with hepatocellular carcinoma. Ethiodol (iodized oil) containing an anticancer drug was infused via the hepatic artery followed by Gelfoam particles. The Ethiodol emulsion was selectively retained in the tumor vessels and also remained in the small daughter nodules that could not be detected by angiography or computed tomography (CT) prior to TAE. Ethiodol remained in the tumor for more than 1 year. Following TAE, main tumors and small daughter nodules appeared as areas of markedly high density on CT. In most patients there was a reduction in the tumor size following TAE, and serum alpha-fetoprotein levels were reduced in all patients whose initial levels had exceeded 400 ng/ml. This method is considered to be effective not only for treatment of hepatic tumor but also useful for evaluation of post-TAE changes in the tumor and diagnosis of small daughter nodules, due to the long-term accumulation of Ethiodol in tumor vessels.