The recent advent of carotid ultrasonography to assess arterial intima-media thickness (IMT) offers the exciting potential for a noninvasive measure of atherosclerosis. Because of its noninvasiveness, carotid IMTallows the extension of anti-atherosclerotic trials to both asymptomatic and frail subjects, for whom coronary angiography might be medically unethical. Because there is currently only limited support for the association of carotid IMT with clinical events or coronary atherosclerosis, the validity of carotid IMT as a potential surrogate for either endpoint has not been established.