Lung cancer is the most common cause of cancer-related mortality in the United States. Surgical resection remains the standard treatment for early stage, non-small cell lung cancer, and limited pulmonary metastases. However, many patients with resectable disease have significant comorbidities which preclude surgical resection. Radiofrequency and microwave ablation are emerging modalities of treatment for these high-risk patients. Here, we review the principles, common devices in use, and treatment results of ablative therapy for lung tumors. J. Surg. Oncol. 2009;100:645-650. (C) 2009 Wiley-Liss, Inc.