Atherosclerosis is the main cause of death in the Western world. The importance of the immune system in the pathogenesis of atherosclerosis is now widely accepted. Here, we demonstrated that circulating dendritic cells (DC) – the most professional antigen-presenting cells in the body - decline in coronary artery disease patients. This is - at least partly - due to impaired differentiation from bone marrow progenitors, but can also be explained by activation and subsequent migration to atherosclerotic plaques or lymph nodes. To be able to exert their function at inflammatory sites, DC need to be resistant to cell death induced by proatherogenic factors, such as oxLDL. Monocyte-derived DC seem to have an effective antioxidant defense system in comparison with monocytes, with high protein levels of peroxiredoxin 2 and glutathione peroxidase 3 among others. This enables them to survive in highly oxidative environments. Whether they enhance or delay the atherosclerotic process, or whether they are differently involved in the various stages of the disease, remains to be established. This book may be useful for anyone who is interested in the immunological aspects of atherosclerosis.