&NA;Severe head injury with resultant basilar skull fracture is the most common etiology for traumatic false aneurysm of the cavernous carotid artery and for traumatic carotid‐cavernous fistula. We present a case of false aneurysm and fistula that occurred as a complication of sphenoidotomy, fortunately a rare etiology of these two serious problems. Because of the current resurgence of trans‐sphenoidal surgery, it is of utmost importance that all neurosurgeons possess an accurate and detailed knowledge of the anatomy of the carotid artery and its intracavernous route.