Although primary surgical excision is the treatment of choice for the vast majority of patients with nasopharyngeal angiofibroma, radiation therapy is also employed as a primary tool or in the cases of tumor recurrence or massive intracranial extension. But, especially in young patients, postradiation sequelae such as osteomyelitis, atrophic rhinitis, thyroid or bone malignancy are of concern. Postirradiation osteosarcoma is a rare, but well-recognized complication of radiotherapy, which comprise roughly 2 to 5 percent of all osteogenic sarcoma. Recently we experienced a case of postirradiation osteosarcoma of the mandible who had treated by radiation therapy for the nasopharyngeal angiofibroma 30 years ago, presently he is ongoing chemotherapy and relatively being well.