The overall results of salvage surgery for lung metastases were evaluated on 174 consecutive patients with primary osteosarcoma below the age of 20, resected in Milan between 1970 and 1988. Seventy-two children treated in the years 1970-1981 were compared with 102 children treated in the years 1982-1988. In the latter period, adjuvant chemotherapy was replaced by neo-adjuvant programs and salvage surgery was applied systematically to all patients with resectable lung metastases through median sternotomy. During the last period, the overall 5 year survival improved significantly from 35% to 58% (P less than 0.001), while the disease free survival rose from 38% to 45% (median 15 vs. 33 months, P = 0.3). The proportion of patients with completely resected lung metastases rose from 17% (7/42) to 55% (27/49), without operative mortality, and the overall survival from detection of lung metastases (including unresected cases) improved from 0 to 28% at 5 years (P less than 0.001). The survival benefit was observed only in the group of children with resected metastases. These data indicate that systematic bilateral pulmonary resection, combined with neoadjuvant chemotherapy, has contributed to improve the final cure rate of childhood osteosarcoma.