Endonasal sinus surgery requires a great deal of training before it can be performed adequately. Due to the complex and variable anatomy and the proximity of important structures, severe complications are possible, even for experienced surgeons. The nasal endoscopy simulator (NES) is an interactive training system for nasal endoscopy and endonasal sinus surgery that combines computer graphics and virtual reality (VR) techniques. This system consists of a graphics workstation, a tracking system for measuring the position of the endoscope and surgical instruments in space, a head model, image data sets of the nasal cavity and paranasal sinus area, and complementary software. The current NES is a visual and auditory VR system that provides both educational and planning options for sinus surgery. The usual resistance when touching relevant anatomical structures is not provided by this release. Therefore, a ''force feedback system'' is implemented that allows for such a response. VR simulation will become an important part of surgical education and planning for individual sinus surgery procedures. The ongoing development of the NES will lead to an improved educational environment for residents in training and practioners.