Hypercholesterolemia is associated with an increased incidence of vascular complications. To assess the actual degree of activation of coagulation systems and vascular disorders in hypercholesterolemia, plasma levels of vascular endothelial cell markers, such as thrombomodulin (TM), tissue-type plasminogen activator, plasminogen activator inhibitor-I (PAI-I), and von Willebrand factor, were measured in 51 patients with hypercholesterolemia. We also investigated the effects of Pravastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on plasma lipid, lipoprotein a, and hemostatic markers. The mean plasma levels of thrombin-antithrombin III complex (TAT), fibrinopeptide A (FPA), TM, and PAI-I were significantly elevated in hypercholesterolemia. Of the hemostatic markers, only TM was significantly increased in patients with ischemic heart diseases (IHD). The mean concentration of total cholesterol and levels of TAT, FPA, PAI-I, and TM were significantly reduced after the Pravastatin treatment. The PIC/TAT ratio was significantly increased in non-IHD patients after treatment, this was not the case in IHD patients. These findings suggested the presence of a thrombogenic state and vascular endothelial cell disorders in hypercholesterolemia; such a state might well be related to hypofibrinolysis.