The demand on virtual planning systems is increasing, in particular for technical pretentious surgical interventions such as intracranial endoscopy. In this paper, a new virtual system for neuroendoscopy is presented. The main purpose of this system is to provide support for the planning and training of neuroendoscopic interventions. The software is applied for virtual endoscopic visualization of three-dimensional magnetic resonance data sets, using a clinical magnetic resonance scanner. Rendering is performed on a Hewlett-Packard unix workstation. Virtual endoscopy provides a three-dimensional view of the cerebral ventricles with good visualization of anatomic details. The rendering system used allows the generation of fly-through sequences through the entire ventricular system in real-time. Navigation is controlled by mouse movements. The visualization of the computer generated intraventricular spaces is adapted to the characteristics of the optical endoscope. The presented virtual neuroendoscopy system is a promising tool for planning and training of neuroendoscopic procedures. It provides the ability to simulate these procedures based on the patient's individual anatomy, prior to surgery.