An aneurysm of the innominate artery could compress the tracheal lumen, and this requires special care. Intubation without intensive monitoring and antihypertensive agents could aggravate the hypercapnia and completely rupture the aneurysm. There are few reports on the airway management of tracheal compression that's caused by an innominate artery aneurysm. We report here on a patient who had a severe hypercapnia after endotracheal intubation above the stenotic area of the tracheal compression, which was caused by an artery aneurysm. Permissive hypercapnia was inadvertently enforced without our knowledge, but the patient recovered without any neurologic problems.