Oxidized low density lipoprotein (oxLDL) is believed to play a critical role in the development and progression of atherosclerosis. Accumulation of oxLDL in macrophages and smooth muscle cells causes foam cell formation, an initial step in the disease. Autoantibodies against oxidatively modified LDL can be used as a parameter that consistently mirrors the occurrence of oxidation processes taking place in vivo. In fact, elevated levels of autoantibodies against oxLDL have been detected in the blood stream of patients with coronary artery disease. Moreover, recent studies indicate a correlation between autoantibodies against oxLDL and the progression of carotid atherosclerosis. Increased serum concentrations of oLAB have also been described in various diseases such as pre-eclampsia and systemic lupus erythematosus. Decreased oLAB titers were observed during septicemia and myocardial infarction. An overview on the clinical applications of oLAB has been published.