Purpose: The objectives of this trial were to estimate the response rate, progression-free survival, and overall survival of patients who received therapy with etoposide and high-dose ifosfamide, and to define the toxicity of this combination when provided with standard chemotherapy in patients with newly diagnosed metastatic osteosarcoma. Patients and Methods: Eligible patients received infusions of 100 mg/m2 per day of etoposide and 3.5 g/m2 per day of ifosfamide for 5 days. Therapy with granulocyte colony-stimulating factor was begun on day 6. This was repeated 3 weeks after therapy was begun. Response was determined at week 6 by both standard World Health Organization response criteria and by pathologic determination of tumor necrosis of the primary tumor. Results: Forty-three patients were registered; 39 were assessable for response and 41 for toxicity and survival. Twenty-eight (68%) of 41 had metastatic sites only in the lung; 12 (29%) had metastatic sites in other bones with or without lung involvement. Four patients (10%) experienced complete response, and 19 patients (49%) experienced partial response, for an overall response rate of 59% ± 8%. The projected 2-year progression-free survival (PFS) for the 28 patients with metastases to lungs was 39% ± 11%. The projected 2-year PFS for the 12 patients with metastases to other bones (with or without pulmonary metastases) was 58% ± 17%. Two patients died as a result of therapy toxicity. Eighty-three percent of patients had grade 4 neutropenia, and 29% had grade 4 thrombocytopenia. Ten patients (24%) had sepsis. Fanconi's syndrome was observed in five patients. Conclusion: The combination of etoposide and high-dose ifosfamide is effective induction chemotherapy for patients with metastatic osteosarcoma, despite significant associated myelosuppression sometimes complicated by infection and renal toxicity. © 2002 by American Society of Clinical Oncology.