Traditionally, the only curative option for patients with liver tumors has been hepatic resection. Unfortunately, only 10%-20% of patients with liver tumors can undergo surgical resection due to limited hepatic reserve, high surgical risk, or unfavorable tumor location. Ablation of liver tumors is currently the main alternative to formal liver resection. Tumor cell death is achieved through a number of technologies, which may be separated into three categories: chemical (percutaneous ethanol injection), cold-based (cryotherapy), and heat-based (radiofrequency and microwave ablation or laser hyperthermia). Although long-term data are limited, ablation may be curative in some patients with a three- and five-year survival rate approaching that of resection. The main factors to success include proper patient selection, excellent diagnostic and procedural imaging, and careful post-procedure management and follow up. Long-term success following tumor ablation will be most dependent on the underlying tumor biology and the ability to achieve a negative margin. Future directions in ablation will include the use of adjunctive agents such as chemotherapeutics, further advances in energy delivery, improved imaging and lesion targeting, and continued refinements of current technology and technique.