Lipoblastoma is a benign tumor which frequently arises in the limbs but rarely in the mediastinum, and is common in children under the age of three years. We report a case of mediastinal lipoblastoma in a 27-month-old female child complaining of dyspnea. Plain radiography demonstrated a huge well-defined mass in the me-diastinum, while CT scanning revealed a soft tissue mass with an internal hypodense portion. When radi-ographic images in children under the age of three reveal a soft tissue mass with a fat component in the mediastinum, especially where there is no calcification or a cystic component, lipoblastoma should be included in the differential diagnosis.