Percutaneous thermal ablation techniques have gained considerable attention as an alternative to surgery for the treatment of malignant liver tumors in selected patients. In particular, image-guided radiofrequency ablation (RFA) is increasingly being used for the local treatment of hepatocellular carcinoma, as well as for metastases to the liver. As a minimally invasive treatment option, this technique has several advantages compared with surgical resection. Benefits include reduction in morbidity and mortality, lower cost, suitability for real-time imaging guidance, use in an outpatient setting and use in patients who are not surgical candidates. The Cool-Tip RFA system has recently received US FDA approval for use in ablating nonresectable liver tumors. This article describes the principles and application of radiofrequency ablation for the treatment of nonresectable hepatic tumors along with the unique features of the Cool-Tip RFA system. Finally, a view into the future suggests that, as the trend towards minimally invasive treatment options for hepatic malignancies continues, RFA will assume increasing clinical application.