Stereotactic endoscopic resection of intra-axial brain tumors using a newly developed endoscopic system consisting of a stereotactic guiding tube and a fine endoscope is reported. The stereotactically inserted guiding tube acts in the place of brain retractors to expose deep-seated pathological lesions, which are then visualized by means of a fine endoscope. The lesions may then be treated by various microsurgical techniques such as laser vaporization. Fifteen intra-axial lesions were operated on by this method using a guiding tube of 8 mm in outer diameter without significant complications. Seven small lesions measuring 3 to 26 mm in maximal diameter were resected totally. Eight large lesions, including two highly vascularized tumors, were examined by biopsy and resected partially through a burr hole with complete hemostasis under direct vision. This system is particularly useful for removing small intra-axial tumors in deep or eloquent areas difficult to resect using ordinary surgical techniques. It will also be applicable for other stereotactic operations that require accuracy and minimum invasiveness with complete hemostasis under direct visualization.