Biphagic pulmonary blastoma (BPB) is one of the rare pulmonary malignant neoplasms. Here, we describe a case of BPB with a histological feature of yolk sac tumor, accompanied with an elevated serum alpha-fetoprotein level (531.1 ng/ml). The tumor was detected in the right upper lobe as a 10-cm mass. The patient underwent right upper lobectomy and mediastinal lymph node dissection. Histological examination revealed that the tumor was composed of immature mesenchymal and epithelial elements, and it was accompanied by foci of yolk sac tumor-like features that showed positive staining for alpha-fetoprotein antibody. Adjuvant chemotherapy consisted of cisplatin and etoposide. After surgery, the serum level of alpha-fetoprotein decreased below normal. Local recurrence was disclosed 27 months after surgery, and radiation therapy was performed. The patient is currently alive 70 months after surgery.