The records of 111 consecutive patients undergoing evaluation for possible carotid endarterectomy at the University of Rochester were reviewed. All patients had noninvasive evaluation (oculoplethysmography-Gee and direct, continuous-wave Doppler ultrasonography) as well as selective carotid angiography. Patients were grouped by clinical presentation to ascertain the relative importance of angiography in determining the need for surgery. Arteriography added nothing to clinical and noninvasive evaluation in over two thirds of patients with hemispheric cerebral symptoms or asymptomatic carotid bruits. In contrast, we found that almost all patients with nonhemispheric symptoms required angiography for adequate evaluation prior to surgery. The implication of these findings on preoperative evaluation of patients with carotid surgery is discussed.