Oxidative damage to lipids and proteins is an important component of atherosclerotic cardiovascular disease (CVD). Studies of oxidation-related molecules are helping to define atherosclerotic mechanisms, and measurements of circulating levels of specific oxidant compounds may improve cardiovascular risk assessment. The present article reviews accumulating data of selected oxidative biomarkers that support their role in providing diagnostic and/or prognostic information. For example, plasma levels of the enzyme myeloperoxidase, which generates the strong oxidizing agent hypochlorous acid, have been found to be correlated with risk for myocardial infarction and endothelial dysfunction. Elevated levels of lipoprotein-associated phospholipase A 2 are associated with coronary artery disease (CAD) and stroke. Oxidized phospholipids play an important role in atherosclerosis. Recent studies measuring circulating levels of oxidized phospholipids have suggested a strong association with CAD, plaque disruption, and response to 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (“statin”) therapy. Isoprostanes correlate strongly with cardiovascular risk factors, but their role in risk prediction is less well defined. Future studies are expected to clarify the role of oxidative biomarkers in the diagnosis and prognosis of CVD and to determine their value in specific clinical populations.