Sixty-nine patients were identified who had survived for at least 10 years after therapy for ordinary-type intramedullary osteosarcoma and for whom adequate follow-up data were available to determine whether second malignancies had developed. Eight patients (11.6%) had developed second malignant tumors, 5 of whom had died of their second malignancies. Although these figures are higher than those expected for cancer incidence and death rates, the differences are not statistically significant.