PURPOSE: To explore the effect of high-dose ifosfamide in first-line treatment for patients < or = 40 years of age with nonmetastatic osteosarcoma of the extremity. PATIENTS AND METHODS: From March 1997 to September 2000, 182 patients were evaluated. Primary treatment consisted of two blocks of high-dose ifosfamide (15 g/m2), methotrexate (12 g/m2), cisplatin (120 mg/m2), and doxorubicin (75 mg/m2). Postoperatively, patients received two cycles of doxorubicin (90 mg/m2), and three cycles each of high-dose ifosfamide, methotrexate, and cisplatin (120 to 150 mg/m2). Granulocyte colony-stimulating factor support was mandatory after the high-dose ifosfamide/cisplatin/doxorubicin combination. RESULTS: No disease progression was recorded during primary chemotherapy, 164 patients (92%) underwent limb-salvage surgery, four patients (2%) underwent rotation plasty, and 11 patients (6%) had limbs amputated. Three (1.6%) patients died as a result of treatment-related toxicity, and one died as a result of pulmonary embolism after pathologic fracture. Grade 4 neutropenia and thrombocytopenia followed 52% and 31% of all courses, respectively, and mild to severe nephrotoxicity was recorded in 19 patients (10%). The median received dose-intensity compared with protocol was 0.82. With a median follow-up of 55 months, the 5-year probability of event-free survival was 64% (95% CI, 57% to 71%) and overall survival was 77% (95% CI, 67% to 81%), whereas seven patients (4%) experienced local recurrence. CONCLUSION: The addition of high-dose ifosfamide to methotrexate, cisplatin, and doxorubicin in the preoperative phase is feasible, but with major renal and hematologic toxicities, and survival rates similar to those obtained with four-drug regimens using standard-dose ifosfamide. Italian Sarcoma Group/Scandinavian Sarcoma Group study I showed that in a multicenter setting, more than 90% of patients with osteosarcoma of the extremity can undergo conservative surgery.