Brain gliosarcoma is a rare variant of glioblastoma multiforme that occurs primarily between the sixth and seventh decades of life. Few cases have been reported in patients younger than nineteen years. We report a four-year-old male with clinical, imaging and pathology compatible with brain gliosarcoma. Beside surgery he was managed with adjuvant radiotherapy and after follow-up is free of recurrence or neurologic deficit. Brain gliosarcoma is highly aggressive and the median survival is related to the extent of surgical resection.