Radiofrequency ablation (RFA) combined with transcatheter arterial embolization (TAE) can increase the volume of coagulation necrosis to treat patients with hepatocellular carcinoma. Furthermore, in clinical practice, RFA combined with TAE using iodized oil and gelatin sponge often induced the sub-segmental or segmental necrosis toward the liver periphery of the ablated lesion. In this study, we compared the CT findings and histological characteristics of peripherally spreading necrosis induced by this combination therapy for 12 patients with hepatocellular carcinoma. In all cases, complete necrosis of ablated lesions and peripherally spreading necrotic areas were confirmed by CT examination. The histochemical (lactate-dehydrogenase, maleate-dehydrogenase, and NADPH-diaphorase) stained specimens, biopsies from ablated lesions and peripherally spreading necrotic areas, were absent suggesting a 100% cellular destruction. No incomplete local treatments after the therapy were obtained during the 4-26 months of follow-up periods. We conclude that RFA combined with TAE using iodized oil and gelatin sponge makes it possible to induce the segmental or sub-segmental necrosis including tumors.