Basic research has provided strong evidence that oxidation of LDL plays an important role in the pathogenesis of atherosclerosis. Several mechanisms have been identified which can lead to LDL oxidationin vivo. Clinical and epidemiological studies have provided circumstantial evidence that oxidized LDL, as measured by serum autoantibody levels, may be associated with the progression of atherosclerotic vascular disease. This review discusses recent findings regarding the presence of oxidized LDL (ox‐LDL)in vivoand the significance of ox‐LDL autoantibody measurements as a tool to predict cardiovascular diseases in various patient populations. Curr Opin Lipidol 9:337–344. © 1998 Lippincott–Raven Publishers