In the past decade the importance of the vascular endothelium in cardiovascular pathophysiology has become more apparent. One substance that is synthesised by and stored in endothelial cells is von Willebrand factor (vWF). When released, vWF seems to mediate platelet aggregation and adhesion to the vascular endothelium. Because the release of vWF is increased when endothelial cells are damaged, vWF has been proposed as an indicator of endothelial disturbance or dysfunction. The availability of such an index of endothelial dysfunction may have clinical value, because measurement of such a marker can be a non-invasive way of assisting in diagnosis or as an indicator of disease progression. The known association between vWF, thrombogenesis, and atherosclerotic vascular disease also suggests that high concentrations of vWF may be an indirect indicator of atherosclerosis and/or thrombosis. In addition, high vWF concentrations have prognostic implications in patients with ischaemic heart disease and peripheral vascular disease.