Statins (HMG-CoA reductase inhibitors) are used widely for the treatment of hypercholesterolemia. They inhibit HMG-CoA reductase competitively, reduce LDL levels more than other cholesterol-lowering drugs, and lower triglyceride levels in hypertriglyceridemic patients. Statins are well tolerated and have an excellent safety record. Clinical trials in patients with and without coronary heart disease and with and without high cholesterol have demonstrated consistently that statins reduce the relative risk of major coronary events by approximately 30% and produce a greater absolute benefit in patients with higher baseline risk. Proposed mechanisms include favorable effects on plasma lipoproteins, endothelial function, plaque architecture and stability, thrombosis, and inflammation. Mechanisms independent of LDL lowering may play an important role in the clinical benefits conferred by these drugs and may ultimately broaden their indication from lipid-lowering to antiatherogenic agents.