This paper describes preliminary work on virtual reality technology applied to liver surgery and proposes several enhancements leading towards realistic surgical simulation. We have built a realistic model of the liver, including the capsule and the four internal arborescences, from a complete set of slice images. A linear elastic biomechanical model was computed using a finite elements method (FEM). This task was performed off line, by pre-computing all possible deformations and force reactions. This approach allows real-time interaction during the simulation. The user interaction is effected by a set of mechanical devices, representing laparoscopic instruments. This haptic interface allows the surgeon to feel the contact forces exerted by the virtual deformable liver-model. The main medical applications of the simulator are in surgical planning, teaching and training. The combination of surgical planning and simulation will lead to improved intervention efficiency and optimal care delivery.