Data obtained in 323 carotid bifurcation endarterectomies and in 77 patients affected by extracranial internal carotid artery stenosis not operated, have been analyzed in relation to patients' age: Group 1 less than or equal to 69 years old (268 cases operated on and 59 not operated), and Group 2 greater than or equal to 70 years old (55 cases operated on and 18 not operated). Among the operated patients, the most important anaesthetic risk factors, the type of neurological symptoms, and the diameter of the lesion did not turn out significantly different between the two age groups, except for the patients operated on because of stenoses less than or equal to 50% of carotid lumen reduction (42 cases in Group 1 and 1 case in Group 2, p less than 0.001). The overall operative mortality rate was 1.8% (6/323 carotid endarterectomies): 1.5% in Group 1 (4/268 cases, 2 due to stroke and 2 to heart disease), and 3.6% in Group 2 (2/55 cases, both due to stroke) (N.S.). The overall neurological morbidity was 0.6%, owing to 2 strokes both found in Group 2 (3.6% of patients greater than or equal to 70 years). Therefore, the overall incidence of fatal and non fatal stroke was 1.8% (6/323 carotid endarterectomies): 0.7% (2 cases) in Group 1, and 7.3% (4 cases) in Group 2 (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)