The prognosis for patients with metastatic osteosarcoma is still poor despite the development of effective adjuvant and neoadjuvant chemotherapy regimens. We have developed caffeine-potentiated chemotherapy for treatment of high-grade bone and soft tissue sarcomas based on the ability of caffeine to enhance the cytocidal effects of anticancer drugs. We report results of caffeine-potentiated chemotherapy for patients with osteosarcoma with pulmonary metastases.