A complex case of carotid-cavernous fistula was treated transvenously by injection of ethyl vinyl alcohol co-polymer into the cavernous sinus after an unsuccessful embolization attempt with detachable coils and liquid adhesive agents. There were no complications. At 3 months the patient's symptoms had resolved completely, and a control angiogram revealed persistent occlusion. The physical properties of ethyl vinyl alcohol polymer justify further investigation of this agent for the treatment of carotid-cavernous fistula.