This study evaluated the effectiveness of intra-aneurysmal coil embolization for large or giant carotid artery aneurysms in the cavernous sinus in seven patients treated by intra-aneurysmal coil embolization from 2001 to 2010. Only one patient showed improved neurological symptoms caused by aneurysmal mass effect during the mean follow-up period of 53.4 ± 27.3 months. Neurological symptoms caused by the aneurysms remained unchanged in two patients, and deteriorated in four. Intra-aneurysmal coil embolization is not considered an effective treatment option for large or giant carotid artery aneurysms in the cavernous sinus.