Continuous electroencephalographic (EEG) monitoring has been generally accepted as the most sensitive detector of cerebral ischemia and need for an intraluminal shunt during carotid endarterectomy. More recently, internal carotid artery stump pressure has been proposed as a simpler and equally reliable indicator of possible inadequate cerebral perfusion. In this study, stump pressure measurements and EEG changes were compared in 80 carotid endarterectomies. The mean stump pressure for patients with ischemic EEG changes was 58 mm Hg, vs 66 mm Hg for those without EEG alterations (not statistically significant). Eleven of 17 patients with definite ischemic EEG changes had stump pressure greater than 59 mm Hg, a value generally equated with adequate cerebral perfusion. EEG interpretations and stump pressure predictions did not agree in 18 of 80 patients (22.5%). Stump pressure measurements should be used with caution as the sole monitor of cerebral ischemia and need for intraluminal shunting.