Fistulas between the cavernous sinus and the carotid artery occur either after trauma or spontaneously. Unilateral exophthalmos is invariably the most conspicuous symptom. Until recently, treatment consisted of some method of occluding the carotid artery involved. Interventional catheter techniques have since been developed that use either Gelfoam embolization or released balloons. The results seem very promising, but long-term results of these new techniques are not yet available. Carotid-cavernous sinus fistulas may be dural or direct, each requiring a different interventional technique. Theredore, it is essential to determine the type involved by selective internal and external carotid angiography. This paper discusses 19 patients with carotid-cavernous fistulas, four of whom were successfully treated by catheter techniques. Gelfoam embolization was used in one case, and in three cases the fistula was closed with the aid of a balloon.