This article describes the principal EEG abnormalities noted during the first 48 hours of cerebro-vascular ischemic accidents due to carotid artery obstruction. No instances of slow delta waves were seen in the 60 cases of transient ischemic accident. In the 162 cases of cerebro-vascular accidents, all EEG abnormalities were correlated with the level of consciousness and thus add little to the clinical data with respect to the prediction of short-term mortality. However, in the 135 patients who presented a cerebro-vascular accident with no alterations of consciousness, the appearance of polymorphic delta waves or spikes (focalized or diffuse) within the first 48 h does significantly predict short-term mortality.