In patients with hepatocellular carcinoma (HCC) surgical resection so far offers potential cure. Due to the frequent association with liver cirrhosis less then 30% of patients with HCC can be resected. In unresectable cases, radiofrequency ablation (RFA) offers an effective treatment alternative. Substantial improvements in the development of powerful generators (up to 250 W) combined with expandable, closed or open-perfused needle electrodes, provide coagulation necroses up to 5 cm in diameter. Most recently primary technical success rates of 85 to 100% were reported. Following RFA of HCC's (diameter up to 2,8 cm) 1-, 2-, 3 and 5-year survival was reported to be 97, 89, 71 and 48%. Low complication rates of 0-12% and a mortality of 0-1% indicate the minimal-invasive character of RFA. Basic principles, technique, indications, contraindications and limitations of percutaneous RFA will be discussed together with a presentation of own cases and a review of literature.