From January 1990 to December 1995 we treated 35 patients (pts) with bone and soft tissue sarcoma with ifosfamide (IFM). Sixteen patients had measurable metastatic pulmonary lesion and 9 had primary lesion. Histology of the tumor included osteosarcoma in 13 pts, Ewing sarcoma in 5 pts, malignant fibrous histiocytoma of bone in 2 pts, synovial sarcoma in 7pts, primitive neuroectodermal tumor in 2 pts, and other in 7 pts. The IFM at the dose of 12-18g/m2 (mean 15. 4g/m2) for 5 to 8 days continuous infusion was administered to patients in each treatment course. The uroprotector, mesna, was also given concomitantly in 60-100% dose of IFM. Eighteen pts received one course of IFM treatment. Other pts received 2 to 8 courses of IFM treatment at three to four week intervals. The overall response rate was 40% (PR in 14 pts, NC in 18 pts, and PD in 3 pts). The response rate of 13 pts with osteosarcoma was 54% (PR in 7 pts) and 30% in 15 pts with soft tissue sarcoma (PR in 5 pts).