Elevated C-reactive protein (CRP) serum level, which is an exquisitely sensitive, objective marker of inflammation, relates to long-term prognosis in patients with stable or unstable coronary artery disease and even in apparently healthy men. CRP is the prototypical, classic acute-phase reactant synthesized in the liver. Several studies have recently shown that elevated CRP levels are associated with a blunted systemic endothelial vasodilator function, indicative of a systemic inflammatory response. Moreover, the identification of elevated CRP levels as a transient independent risk factor for endothelial dysfunction might provide an important clue to link a systemic marker of inflammation to atherosclerotic disease progression. This editorial addresses the role of C-reactive protein in endothelial dysfunction.