The authors describe a case of a primary brain tumor composed of both gliomatous and sarcomatous elements. Surgical specimen, six months preceding his death, shows anaplastic astrocytoma with moderate endothelial proliferation of the blood vessel. Huge, relatively circumscribed subcortical tumor extending to the epidural space is observed on cross section of the autopsy specimen. Epidural mass is composed of sarcomatous tumor and subcortical one reveals islands of sarcomatous tissue surrounding by gliomatous stroma. In deeper region of the brain, proliferation of astrocytes and vascular hyperplasia are noticed. This tumor may be considered analogous to the gliosarcoma, which is described by Feigin. The histogenesis of the mixed tumor is discussed with special reference to the gliosarcoma.