The aim of our study was to investigate the prevalence of MTHFR gene polymorphisms, factor V G1691A-Leiden mutation, prothrombin G20210A mutation, plasminogen- activator inhibitor PAI-1 675 4G/5G mutation and hyperhomocysteinemia correlated with cardiovascular risk factors in the group of patients with CVST. The gene discussed is F2; the disease is hyperhomocysteinemia.