The results of recent trials indicate that statin treatment reduces not only the risk of coronary heart disease, but also the risk of stroke, in patients with existing heart disease. The need for the treatment of such patients is now generally recognized. Mechanisms for risk reduction include the retardation of plaque progression, plaque stabilization, and reducing the risk of coronary events. Questions remain regarding the discrepancy between epidemiological data and statin trials data, the precise mechanism of action of statins, and their role in the prevention of recurrent stroke in individuals who have experienced a previous stroke or transient ischemic attack but are free of coronary disease.