Two cases of giant intracavernous aneurysms treated by high now bypass with saphenous vein graft between the external carotid artery (ECA) and branches of the middle cerebral artery (MCA) are presented. Very often these aneurysms are unclippable because they are fusiform or have a large neck, Occlusion of the internal carotid artery (ICA) is the treatment of choice in many eases, This procedure has however a high risk of brain infarction. Revascularization of the brain by extra-intracranial anastomosis between the superficial temporal artery (STA) and branches of the MCA is frequently performed. This procedure provides however a low flow bypass and brain infarction may occur, We report two cases of giant cavernous sinus aneurysms treated by high flow bypass and endovascular balloon occlusion of the LCA, Immediate high now revascularization of MCA branches was achieved and the patients showed no ischemic events. Follow-up of 8 and 14 months alter operation shows patency of the venous graft and no neurological deficits, Angiographic control examination showed complete aneurysm occlusion in both cases.581162168