The high definition television (HDTV) system is introduced to microneurosurgery. Five cases with intracranial lesions: three cerebral aneurysms (giant aneurysms of the anterior communicating artery and internal carotid artery, aneurysm of the basilar artery), one acoustic neurinoma and one skull base meningioma, were operated on under the microscope using the HDTV system. The surgical procedures of each case were relayed and recorded by the system. In two of the five cases, we used two sets of HDTV system to produce stereoscopic projection. The HDTV system provided us with images of superior quality with a distinctly greater resolution than ordinary video systems.