Four patients with fixed neurological deficits due to occlusion of the middle cerebral or the internal carotid arteries, and with collateral circulation to their territory diagnosed by angiography, recovered after extra-intracranial arterial anastomosis. Functional recovery was seen since the first hours after bypass in three cases and the first few days in the other. Angiographic demonstration of collateral circulation to the territory of an occluded cerebral artery seems to be useful in the selection of patients with fixed neurological deficits for extra-intracranial arterial anastomosis, mainly when other methods are not available.