Recent studies of the literature indicate that arteriosclerotic lesions located in the remnants of bifurcation and proximally to an occluded internal carotid artery can represent sites for the origin of emboli. Through the collateral circulation, these emboli can reach the homolateral cerebral territories producing further ischemic events. Two groups of patient, with angiographically proven internal carotid artery occlusion, one with, and another without irregular arteriosclerotic lesions (IAL) in the stump and/or external carotid artery, were followed up in order to determine the frequency of delayed post-occlusion ischemic events in each group. Ipsilateral events occurred more frequently when there was a stump associated with IAL in the remnants of bifurcation and signs of ophtalmic collateral circulation. This association may have prognostic value and should be considered before performing bypass procedures.