Osteosarcoma very rarely metastasizes to the heart. Thirteen cases have been reported in the literature so far. Diagnosis in some of these cases was made during investigation for severe cardiac failure and in most of them at autopsy. Our patient, a 13-year-old girl, showed right pulmonary metastases on chest x-ray 1 year after above knee amputation for osteosarcoma of the distal femur. Routine preoperative computerized axial tomography (CT Scan) revealed a calcified lesion in the heart in addition to the pulmonary metastases. She was very active and completely asymptomatic. Two-dimensional echocardiography, angiography, and right and left heart catheterizations were done. This revealed a large mobile metastatic lesion in the right ventricle. The intraventricular tumor was successfully removed, and 12 days later she had a second thoracotomy for removal of pulmonary metastases. Nine months after her intraventricular metastasis was removed she developed a solitary right pulmonary metastasis. This was successfully resected. Now, 10 months later, she is disease free and completely asymptomatic.