A 73-year-old male presented with bloody sputa for a month. Chest computed tomography (CT) showed a large mass about 7 cm in diameter in the right lower lobe. Bronchoscopic curette cytology revealed class V and a suspected adenocarcinoma, although a systemic evaluation demonstrated no metastatic lesion. The patient underwent a right lower lobectomy and mediastinal dissection. A biphasic pulmonary blastoma was histologically diagnosed by a characteristic finding that it was mainly constituted of immature tumor tissue that had both epithelial and mesenchymal components. No mediastinal lymph node metastasis was proven. Stage T2N0M0 disease was diagnosed, and the patient chose not to undergo postoperative adjuvant chemotherapy; he remains well without recurrence 36 months after the operation.