Five patients with primary osteosarcoma who were treated effectively with chemotherapy and resective surgery and in whom a metachronous tumor subsequently developed in another site but who never had evidence of pulmonary metastases are described. The original bone scans of the five patients showed only the primary site as being involved. After diagnosis and treatment of the initial tumor, at intervals ranging from 12 to 78 months (average, 39 months) another osteosarcoma developed in the patients at a distant bony site. After diagnosis and treatment of the second osteosarcoma, followup of these patients for a mean of 77 months (range, 24-96 months) after the appearance of the metachronous tumor and for a mean of 118 months (range, 99-150 months) after the diagnosis of the primary lesion showed that none had pulmonary metastases develop. No recurrences of the local tumors have occurred and four of the patients currently are alive and free of disease. One of the patients had a fatal acute myelogenous leukemia develop 144 months after the discovery of the primary osteosarcoma and 86 months after the appearance of the metachronous disease. At the time of her death, however she had no evidence of osteosarcoma in any site.