The last two decades have seen a growing interest in the mechanisms of interaction between vascular endothelium and blood cells. Endothelial activation and the structure and function of adhesion molecules involve an extensive family of proteins permitting the great variety and specificity of cell-cell and cellmatrix interactions. This field of research has broad implications for embryogenesis, differentiation, and tissue physiology and pathophysiology. Adhesion molecules are integral to such fundamental processes as inflammation, atherosclerosis, and immune response. Our recent ability to measure the soluble part of adhesion molecules in biological fluids provides us with an indirect estimate of vascular inflammation. This review covers the latest developments together with their clinical and pathophysiological implications...