Radiation therapy has an important role in postoperative treatment of neoplasms originated from central nervous system, but may induce secondary malignancies like as sarcomas, gliomas, and meningiomas. The prognosis of radiation-induced osteosarcomas is known as poor, because they has aggressive nature invasive locally and intractable to multiple treatment strategies like as surgical resection, chemotherapy, and so on. We report a case of radiation-induced osteosarcoma developed from skull after 7 years of craniospinal radiotherapy for pineoblastoma.