Ex.traosseous osteogenic sarcoma is exceedingly rare although bone formation occurs commonly in different reactive processes or neoplasms. Most of this tumors occurred in the lower extremities of middle aged people. The overall prognosis is grave and local recurrence following simple local excision possibly contributes to the poor prognosis. An agressive surgical approach including major amputation is recommended as the primary form of treatment. We have experienced a case of extraosseous osteogenic sarcoma of left gluteal region at the site of therapeutic irradiation for cervical carcinoma 16 years previously.