From Dec. 1989 to Apr. 1992, we completed the treatment of sixteen patients of Ennekings stage IIB osteosarcoma of the extremities with our high-dose methotrexate (HDMTX) protocol. Among 16 patients, 10 were males and 6 were females. Their ages were ranged from 11 to 23, with an average of 15 years. The locations of lesion were distal femur in 10 cases, proximal tibia 3 cases, proximal femur one case, proximal fibula one case, proximal humerus one case. Preoperatively, two cycles of HDMTX was done. Surgery was done around 10th weeks from the initiation of chemotherapy. One case of amputation and 15 cases of limb-salvage operations were performed. The surgical specimens were mapped pathologically to determine the effectiveness of preoperative chemotherapy. Response criteria were based on Huvos' grading system. Histologically, 14 cases were of the osteoblastic type and 2 were chondroblastic. Histological response to preoperative chemotherapy showed Grade 1V in 6 cases, Grade III 2, Grade II 4, and Grade I 4 cases. The average necrosis rate was 75.1%. Tailored postoperative chemotherapy were done according to the chemotherapy response. In good responders we used same regimen as preoperative chemotherapy but in poor responders we switched to the regimen including adriamycin-cisplatin and Bleomycin-Cyclophospha-mide-Actinomycin-D. The follow-up period ranged from 11 to 27 months with and average of 16.9 months. One patient showed metastasis to the rib and pelvis at 5 months postoperatively, and one patient showed local recurrence at 8 months postoperatively. These two patients are alive with disease until final follow-up (2 year actuarial survival rate; 100%). The Kaplan-Meier's 2 year continuously disease free survival rate was 87.5%.