The purpose of this study was to determine the importance of hypoperfusion ischemia as a cause of stroke during carotid endarterectomy (CEA). A retrospective analysis of 128 consecutive CEA procedures were examined in patients at risk for hypoperfusion ischemia, namely, patients with occlusion of the contralateral carotid artery. All procedures were performed under general anesthesia without the use of a temporary indwelling shunt. Sixty-one percent of patients had cerebrovascular symptoms preoperatively and 39% were asymptomatic. The degree of stenosis of the carotid artery was 80%-99% in 67% (86/128) of patients, 60%-79% in 25% (32/128), 20%-59% in 7% (9/128), and 0-19% in 0.8% (1/128). The perioperative mortality was 0.8% (1/128), the incidence of permanent neurologic morbidity was 1.6% (2/128), and the incidence of transient neurologic morbidity was 3.9% (5/128). In conclusion, these data suggest that hypoperfusion ischemia is a rare cause of stroke during CEA even in patients with occlusion of the contralateral carotid artery and that CEA can be performed safely even in patients with contralateral occlusion without the use of a temporary indwelling shunt.