Vascular endothelium plays a key role in the control of haemostasis and thrombosis. The main reactions involved in the regulation of platelet reactivity, blood coagulation and fibrinolysis take place at the luminal surface of endothelial cells. Following exposure to certain pathological stimuli, remarkable functional changes of the endothelial cells occur, including downregulation of antithrombotic mechanisms and upregulation of prothrombotic activities. Based on the recent knowledge of vascular endothelial function, a better understanding of the pathogenesis of atherothrombosis is expected.