von Willebrand factor (vWf), risk factors for atherosclerosis, body mass index (BMI) and waist-to-hip ratio (WHR) were measured in 108 non-diabetic patients attending lipid and vascular disease clinics and in 107 normal asymptomatic controls. High levels of vWf and increased BMI relative to controls were found in patients with hyperlipidaemia and vascular disease, but WHR was higher only in patients with vascular disease. Total serum cholesterol concentration (P < 0.001), systolic blood pressure (P < 0.001), smoking (P < 0.02) and BMI (P < 0.001), but not WHR, were associated with vWf. As raised levels of vWf are a probable indicator of endothelial damage in vascular disease, these data suggest that obesity has an adverse influence on the endothelium and may help explain its link with cardiovascular disease.