The past 4 years have seen a growing interest in cholesterol metabolism and its relationship to Alzheimer's disease. From the first report linking cholesterol and beta-amyloid metabolisms to the recent positive report on the use of atorvastatin (Lipitor, Pfizer Inc.), a cholesterol-lowering drug, in mild-to-moderate Alzheimer's disease, this review examines the scientific progress pertaining to etiopathology of Alzheimer's disease over the past 15 years and the central role of lipids in this field of research. The role of key proteins involved in this metabolic pathway such as apolipoprotein E, lipoprotein lipase, caveolin, hydroxy-methylglutaryl Coenzyme A reductase, low-density lipoprotein receptors, cholesterol 24-hydroxylase, acyl-coenzyme A:cholesterol acyltransferase and beta-amyloid are discussed.