Metastases of osteosarcoma in the mouth are rare, and only few cases have been described. We present a case of telangiectatic osteosarcoma of the femur in a 15-year-old girl, who developed metastases in the humerus, lungs and retromolar area 4 years after initial diagnosis and treatment. The girl died 2 months after the diagnosis of metastases despite treatment with chemotherapy. This report emphasizes that telangiectatic osteosarcoma has a very poor prognosis, particularly when multiple metastases develop.92104106