Resection and thermal ablation procedures are frequently used for the treatment of primary and secondary liver tumors. Various tools for the virtual planning of liver resections and ablation are available and some of them are already used clinically. Resection planes and ablation volumes can be optimized for sufficient safety margins while preserving a maximal amount of functional liver tissue. Connecting the pre-operative planning with intraoperative guidance based on the 3D imaging data would be desirable. Interactive image guided surgery enables visualization of the actual spatial location of the surgical instrument on preoperatively acquired images in real time. However, extensive soft tissue deformations during open and laparoscopic surgical and ablative procedures may occur, causing unacceptable inaccuracies. The current focus of research is the adaptation of the preoperative virtual planning models to surgery by using intraoperative imaging and biomechanical models. In contrast to open and laparoscopic surgical procedures percutaneous punctures can be performed with high accuracy under stereotactic conditions. Important prerequisites include patient immobilization, respiratory triggering and intraoperative imaging. Due to the high accuracy of probe positioning the virtual preoperative ablation plan can be precisely transferred into the real patient. A total of 350 patients with primary and secondary liver tumors have already successfully been treated with stereotactic radiofrequency ablation (SRFA). Due to its low complication rates and similar local recurrence and survival rates as compared to conventional surgery SRFA is an attractive alternative for the treatment for primary and secondary liver tumors.