The basic principle of radiofrequency ablation is that the deposit of electromagnetic energy in a tumor causes heat ("cooks the tumor") and thereby destroys it. In the liver, this ablation may be performed percutaneously (by needles) or surgically (laparotomy, laparoscopy). Guidance by an imaging technique is necessary: ultrasound, CT or magnetic resonance imaging. The principal hepatic indications are hepatocellular carcinoma and hepatic metastases smaller than <5 cm. There is no associated mortality and only slight morbidity, due principally to hemorrhage, infection or stenosis of the bile ducts. Results show a 5-year survival rate of 40% for hepatocellular carcinoma and 22% for metastases.