Evaluation of carotid intima media wall thickness (IMT) by using ultrasonography is a validated quantitative method for assessing atherosclerosis, and is closely correlated with pathological findings observed in the carotid artery. Furthermore, the appearance of atherosclerosis in the carotid artery has been highly associated with atherosclerosis in the aorta and a close relationship has been observed between IMT and the incidence of coronary heart disease. In the present study, we investigated the association of risk factors for atherosclerosis with pre-clinical atherosclerosis as evaluated by IMT in native Japanese and Japanese Americans living in the United States.