Carotid endarterectomy may carry a substantial risk of morbidity and mortality from major stroke, thus offsetting any statistical benefit in reduction of future stroke. Because of the disturbing ranges in the incidence of stroke morbidity and mortality reported from the several institutional series studying carotid endarterectomy, the authors undertook a prospective review of 142 consecutive carotid endarterectomies performed for symptomatic atherosclerotic occlusive vascular disease on the neurosurgical service. The University of Alabama Hospital. Preoperative risk assessment was performed in each case according to the Mayo Clinic classification system. The overall mortality rate was 1.4% and the major stroke morbidity rate was 0.7%, for a combined major morbidity and mortality rate of 2.1%. The incidence of minor neurological morbidity was 1.4%. There was no morbidity or mortality in the Grade I and II (low-risk) patient groups. This low combined major morbidity and mortality rate of 2.1% for carotid endarterectomy causes the surgical stroke-free survival curve to intersect the medical stroke-free survival curve at an earlier point in time, and thus demonstrates the greater reduction in risk of stroke which accrues over time for the surgically treated patient.