A simultaneous operation was successfully performed on a 70-year-old man with recurrent aortic arch aneurysm and squamous cell carcinoma of the lung. Via a left thoracotomy, left lower lobectomy with lymph node resection was performed, and via the same incision, aneurysmectomy with graft replacement was performed under the hypothermic cerebral circulatory arrest. The patient was readmitted because of brain metastasis 10 months later, and died 11 months postoperatively. The present report suggests that selected cases of thoracic aortic aneurysm with malignant tumor are safely able to undergo simultaneous operations. This is the first report in Japan of aortic arch aneurysmectomy and lobectomy performed during the course of one operation.