We have developed computer assisted stereotactic methods for the resection of deep seated and centrally located intracranial tumors. Data base acquisition consists of stereotactic computed tomography (CT), magnetic resonance imaging (MRI) and digital angiography (DA). A tumor volume is computer interpolated from CT and MRI defined tumor boundaries. The surgical approach or viewline is selected from stereotactic DA images and anatomically defined by MRI and expressed in mechanical settings on the stereotactic frame. During stereotactic resection the computer displays the position of a stereotactically directed retractor with respect to tumor slices cut perpendicular to the viewline. It is theoretically possible to resect all of the lesion detected by the imaging studies utilizing this method. To date we have performed 267 computer-assisted stereotactic microsurgical resections of a variety of deep seated intracranial tumors with a morbidity rate of 10.5% and mortality rate of 1%. The procedure provides a method by which the surgeon can maintain three dimensional orientation during the resection of CT and MRI defined deep seated intracranial lesions.