Coronary artery disease (CAD) is the largest cause of morbidity and mortality in the world. A relationship between CAD and elevated levels of low-density lipoprotein cholesterol has been established. However, risk assessment limited to low-density lipoprotein fails to identify a significant portion of patients at risk for CAD. Remnant lipoproteins, derived from very low-density lipoprotein and chylomicrons, have been considered atherogenic. Recently, a simple and reliable immunoaffinity separation method for the isolation of remnant-like particles (RLP) has been developed. It has been shown that RLP cholesterol levels are significantly correlated with CAD, and thus cellular mechanisms have been determined by which RLP cholesterol causes progression of atherosclerosis. Measurement of RLP cholesterol is useful for the assessment of risk and the evaluation of therapy in patients at risk for CAD.