Five patients with tumors in the anterior skull base were surgically treated using the transbasal approach, which permits removal of the tumor, repair of the dura mater, and reconstruction of the skull base in a one-stage procedure. By using autologous materials for the bone graft and pedunculated pericranial flap for the reconstruction, the intracranial structures are separated from the air-filled nasal and paranasal cavities. No postoperative complications such as wound infection and leakage of cerebrospinal fluid were encountered. The use of this surgical technique makes it possible to extirpate brain tumors that heretofore have been considered unresectable.