Pulmonary liposarcoma is extremely rare with 6 cases previously reported in the English literature. The following is a report of a 36-year-old man with pulmonary liposarcoma. The patient had chest pain and a mass shadow in the right lower lung field was revealed on a chest X-ray film. A computed tomography and magnetic resonance imaging showed a heterogeneous tumor, compressing the right lower lobe of the lung. Because of the fatty tissue component in the tumor on the chest computed tomography, and the appearance as an extrapulmonary mass, preoperative diagnosis was posterior mediastinal liposarcoma. But thoracotomy revealed that the tumor originated from the lung. Right lower lobectomy and lymph node dissection was carried out with no additional therapy. The pathological diagnosis was pleomorphic liposarcoma originated from the lung. Two months after the operation, the patient died of respiratory failure due to local recurrence.