Purpose: A 6-year-old boy with osteogenic sarcoma of the left humerus underwent bone scintigraphy. Tc-99m MDP was accumulated not only in the primary tumor but also in the osseous and extraosseous (pulmonary and pericardial) metastases. Osteogenic sarcoma directly produces osteoid, both in the primary and metastatic lesions. Tc-99m MDP is avidly taken up by tumor osteoid. At initial presentation, only 2% of cases have both pulmonary and osseous metastases. The patient had osseous, pulmonary, and pericardial metastases at presentation. This case presents that increased uptakes of Tc-99m MDP by the primary and metastatic tumor were demonstrated on bone scintigraphy at presentation.