The plasma vWF levels in patients with CVD were determined using ELISA technique with two monoclonal anti-human vWF antibodies. The results showed that the vWF values in the acute stage of CVD increased significantly. They gradually decreased third weeks after the onset of the CVD. The vWF in the chronic stage of CVD remained higher than normal, but lower than that in the acute stage. The plasma vWF values showed practically no difference in either cerebral infarction or hemorrhage. The average plasma vWF level in the patients with TIA was higher than that in the controls but lower than that in the patients with complete stroke. It was found that the plasma vWF correlated with platelet aggregation induced by ADP constantly, but not with other risk factors. It was considered that elevated vWF would rather be regarded in CVD as a relatively independent risk factor.