Between March 1983 and June 1986 127 patients with localized osteosarcoma of the extremity were treated with neoadjuvant chemotherapy. Preoperative chemotherapy consisted of two cycles of methotrexate (MTX) (high or moderate doses) followed by 6 days by cisplatin (CDP). Surgery was an amputation or a rotation plasty, or a limb salvage. Necrosis was good in 52% of cases, fair in 36%, and poor in 12%. Postoperative chemotherapy consisted of Adriamycin (doxorubicin [ADM]) and bleomycin (BCD) for poor responders; and ADM, MTX, and CDP for fair responders. Good responders were treated as fair responders or with only MTX and CDP. At a 47-month follow-up, 66 patients remained continuously disease free and 61 patients developed metastases. Six of these patients had also a local recurrence. According to the grade of necrosis, the cumulative disease-free probability at 5 years was 67% for good responders, 42% for fair responders, and for poor responders 10% at 45 months. According to the doses of MTX, survival at 5 years was 58% for patients who received high doses and 42% for patients treated with moderate doses. No differences in the rate of survivors were observed between amputated patients and patients treated with limb salvage. The authors conclude that (1) a limb salvage procedure is possible in about 70% of cases and as safe as demolitive surgery, if adequate surgical margins are achieved; (2) good responders have a better prognosis than fair and poor responders if postoperative chemotherapy is sufficiently prolonged and also includes ADM; (3) a different postoperative chemotherapy for poor responders did not improve their prognosis; and (4) a multidrug regimen using high doses of MTX is probably more effective than moderate doses.