Blood cholesterol and LDL levels are well-established risk factors for cardiovascular disease and, in particular, coronary heart disease. In recent years, the role of LDL in the pathogenesis of atherosclerosis, the underlying cause of coronary heart disease, has been studied extensively. These studies have highlighted the complexity of atherosclerotic processes and identified oxidative damage and inflammation as important components of the process. In addition, the formation and possible involvement of various oxidized lipids in atherosclerosis have been identified by the studies. The oxidized lipids include the products of oxidative enzymes, located in the vasculature, as well as nonspecific oxidation products. Many of these lipids have been found in atherosclerotic plaque and have potent bioactivities. Moreover, these oxidation products and, reactive oxygen and nitrogen species, have been linked with cellular signaling pathways that can influence the development of atherosclerosis.