The rationale of preoperative chemotherapy for osteosarcoma requires: eradication of microscopic metastatic foci which have already occurred in many patients with osteosarcoma, determination of a more effective form of postoperative adjuvant chemotherapy and easier and safer limb-salvage procedures through clearer marginal definition with reduction of primary lesions. In this paper, chemotherapeutic effects on the 5-year survival rate were analyzed for 49 patients with primary non-metastatic osteosarcoma of the extremities treated with radical surgery. The efficacy of preoperative chemotherapy was assessed in 11 cases of osteosarcomas treated with systemic chemotherapy as a preliminary study. As to the 5-year cumulative survival rate, the systemic group (20 cases) showed a level of 56.7%, which was significantly higher (p less than 0.05) than the figure of 13.8% in a historical retrospective group (29 cases). In assessing the effective tumor response to preoperative chemotherapy, a close correlation between the tumor necrotic ratio and the ratio of decrease of serum alkaline phosphatase was revealed. Seven (63.6%) of 11 cases showed correlation of the tumor necrotic ratio with the ratio of decrease of serum alkaline phosphatase. The tumor necrotic ratios calculated were relatively definite (50-60%) in the CDDP group (3 cases), varied (10-70%) in the HDMTX group (4 cases), and low (less than 40%) in the ADR group (4 cases), regarded as a control group in further studies.