Leukocytes play a critical role in both the initial steps of atherogenesis and the late events of plaque instability and thrombosis. Leukocyte-endothelial cell adhesion molecules (CAMs) modulate the interaction between circulating leukocytes and the vessel wall. Levels of soluble CAMs are increased in patients with dyslipidemia or other risk factors, and levels can be reduced by lipid-modifying therapy. Novel markers of inflammation and atherosclerosis may be useful to identify high-risk individuals and to assess the efficacy of antiatherosclerotic therapy.