A case of left temporal gliosarcoma is reported. The patient was a 40-year old man who had headache, behavior change, dysphasia, and mental confusion for about 2 months duration. On brain CT, a large partially cystic mass with homogeneous enhancement was located at left temporal lobe and associated with remarkable peritumoral edema and mass effect. Angiographic tumor vascularity was faintly visualized. Surgical subtotal resection of the tumor and post-operative radiotherapy offered transient symptomatic improvement, being followed within several months by clinical deterioration and regrowth of the tumor on brain CT. Light microscopic studies of the H & E and special stained specimens showed two different components within the tumor in a mixed fashion, i.e. intermingled glioblastoma multiforme and fibrosarcoma. Electron microscopic study of the sarcomatous cells disclosed intracytoplasmic Weibel-Palade-like bodies, a specific marker of endothelial cells. The fibrosarcomatous component of gliosarcoma is believed to be originated from malignant transformation of the hyperplastic endothelial cells within the anaplastic glioma. Literature concerned with gliosarcoma is reviewed.