Immune responses against oxidized forms of LDL play a critical role in activation and regulation of the inflammatory process that characterizes all stages of atherosclerosis. In humans oxidized LDL is targeted by both IgM and IgG autoantibodies. Immunization of hypercholesterolemic animals with oxidized LDL has been shown to inhibit atherosclerosis demonstrating that at least some of these immune responses have a protective effect. The identification of the structures in oxidized LDL that are responsible for activation of immunity has made it possible to develop novel therapeutic approaches for treatment of atherosclerosis based on active (vaccines) and passive (antibodies) immunization. Studies performed in atherosclerosis-prone mice demonstrate that both peptide-based vaccines and recombinant IgG targeting epitopes in oxidized LDL significantly reduce atherosclerosis. There is also evidence antibodies against oxidized LDL could also be used for imaging atherosclerosis.