In five large-scale prospective studies the predictive value of hemostatic parameters indicating the occurrence of arterial thrombotic diseases has been estimated in healthy individuals. All the studies have consistently found a statistically significant association between hyperfibrinogenemia and arterial thrombotic diseases. In two studies, increased levels of factor VII were associated with an increased incidence of ischemic heart disease. The relationship between arterial occlusive diseases and plasma levels of fibrinogen or factor VII was closer than that for other well established risk factors such as plasma cholesterol. These data indicate the important pathogenetic role carried out by alterations of the clotting system in occlusive arterial diseases.