Radiofrequency interstitial hyperthermia has been used for percutaneous ablation of hepatocellular carcinoma, under ultrasound guidance in local anesthesia. Conventional needle electrodes require a mean number of 3 sessions to treat tumors of diameter < or = 3 cm. Tumors up to 3.5 cm in diameter can be treated in 1 or 2 sessions by expandable needle electrodes. With both methods in all treated cases, ablation of tumors was obtained. In a group of patients with long follow-up, survival rate at 5 years was 40%. In a mean follow-up of 23 months 41% of patients had recurrences (local recurrences in 5%; new lesions in 36%), which often could be retreated by a new course of radiofrequency application. In recent experience large hepatocellular carcinomas (up to 6.8 cm in diameter) were treated by a combination of segmental transcatheter arterial embolization followed by radiofrequency application. In this way most tumors were ablated in one session of radiofrequency therapy. No fatal complications were observed. Major complications were: strong pain due to capsular necrosis in one patient; hemotorax in one case; a fluid collection in the site of ablated tumor in one patient treated by combination of transcatheter arterial embolization and radiofrequency application.