82-year-old man was admitted with an abnormal shadow on the chest roentgenogram. Computed tomography showed a 2.8 x 2.4 cm solid tumor in S3 of the left lung. Transbronchial lung biopsy revealed adenocarcinoma and a left upper lobectomy (ND2a-1) was performed. The tumor consisted mainly of tall columnar clear cells, and no morules were found. Immunohistochemically, the tumor was positive for alpha-fetoprotein (AFP) and p53. Accordingly, we made the histological diagnosis of high-grade fetal adenocarcinoma of the lung, pT2N0M0, stage IB. The patient was not received adjuvant therapy and has been doing well without any tumor recurrence for 3 months postoperatively.