Seventeen patients with Ewing's sarcoma were divided into 3 groups according to treatment. Ten patients were treated with complete chemotherapy; 9 with VACA protocol, composed of vincristine, actinomycin-D, cyclophosphamide and doxorubicin, and the remaining 1 with T-11 protocol. Four were given incomplete VACA protocol, and another 3 received no chemotherapy. Clinical results were evaluated in the three treatment subgroups described above. All patients without systematic chemotherapy died from lung metastasis within 1 year of the initial treatment. Three of 4 patients who were given incomplete chemotherapy died after a mean survival period of 17.7 months, and one developed cancerous pleuritis after 38 months. In the group receiving complete systematic chemotherapy, 5 of 10 patients are alive, and 2 have been disease-free for more than 3 years. Distant metastasis is likely when viable cells persist at the site of the primary tumor, even if the tumor size has been considerably reduced by preoperative chemotherapy. Therefore, immediate initiation of intensive chemotherapy and maintenance for the full course of therapy can improve the prognosis of Ewing's sarcoma.