Aims: Osteosarcoma is the most common, non-hematopoietic primary malignant tumor of bone. Osteosarcomas develop de novo in apparently normal bone. However, some benign bone tumors and non-neoplastic conditions may undergo malignant transformation into osteosarcomas. Such osteosarcomas are called secondary osteosarcoma. The scope of this article is to report on a ten-year experience of secondary osteosarcoma in a single institution.