Following the demonstration that patients with deep venous thrombosis of the lower extremities have a significant higher prevalence of carotid plaques than matched control individuals, numerous studies have consistently shown that patients with venous thromboembolism -especially those with events of unknown origin -have a remarkably higher risk of developing subsequent arterial thrombotic events than control subjects. The two vascular disorders share several risk factors (including age, obesity, smoking habit, diabetes mellitus, hypertension, hypertriglyceridemia, and metabolic syndrome) and the abnormal elevation of markers of endothelial dysfunction (such as microalbuminuria and the plasma levels of soluble P-selectin and von Willebrand factor). These findings have potential implications for both research and medical practice. Patients with venous thromboembolism could be examined for asymptomatic atherosclerosis, in order to modify the risk profile in those with abnormal test results. Measures could include appropriate counseling about lifestyle changes, control of risk factors for atherosclerosis and the use of drugs, such as statin and aspirin, whose effectiveness in reducing the risk not only of arterial but also of venous thrombotic disorders has recently been shown.