Intravenous cis-Diamminedichloroplatinum-II (CDP) was administered to 10 patients with osteosarcoma to treat the primary tumor in 8 and bone metastases in 2. Three patients also had pulmonary metastases. The intent was to deliver 7 courses (150 mg/M2 q 2 weeks) over 3 months (total cumulative dose 1050/mg/M2). However, this was only accomplished in 2 patients; in the remaining 8 the full course was not administered because of temporary renal insufficiency (3), tumor escape (1) and apparent response after 4-6 courses suggesting that no further benefit would accrue (4). Overall, clinical and/or radiologic responses were observed in 9 patients. In 6 of 9 tumors subjected to surgical resection (66%), necrosis in excess of 65% was observed. Optimum results were achieved with a cumulative dose of 600 mg/M2 administered over 6 weeks. These results suggest that intravenous CDP may be as efficacious as intra-arterial CDP which has produced similar responses.