We present a rare case of adenosquamous carcinoma of the lung in a patient with complete situs inversus. The patient was a 76-year-old woman with the chief complaint of hemosputum. Chest X-ray and computed tomography (CT) scans of the thorax showed a mirror image of the organs and vessels and revealed a tumor 3.5 cm in diameter, in the left lower lung field. She was referred and admitted to KKR Hokuriku Hospital, Kanazawa, Japan to undergo surgery. Bronchoscopy showed a mirror image of the usual arrangement of the bronchi, and 5 segmental branches in the left lower bronchi. During surgery, care was exercised when intubation with the Univent^® bronchial tube for one-lung ventilation. On thoracotomy, the gross appearance of the left lung and the arrangement of the pulmonary vessels and the bronchi corresponded to those normally found on the right side. We were successful in performing a left lower lobectomy. Postoperative diagnosis confirmed an adenosquamous carcinoma with localized pleural dissemination as p-t4n1m0, stage IIIa. Preoperative imaging, including CT, bronchoscopy, and angiographic examination of the patient, will be useful for prevention of vascular or bronchial injury during surgery in patients with complete situs inversus undergoing lung resection. Possible vascular or bronchial anomalies should always be taken into consideration while operating on these patients.