We report a case involving a patient undergoing carotid endarterectomy in whom transcranial doppler monitoring demonstrated impaired cerebral blood flow during the initial dissection of the carotid artery, during cross-clamping of the carotid artery, and after the shunt was kinked inadvertently. Only when the carotid artery was cross-clamped were these ischemic changes also seen by electroencephalography. During the other episodes, the electroencephalography tracings demonstrated no detectable changes. This case illustrates the importance of using multiple modalities to determine the adequacy of cerebral blood flow and neuronal integrity.