Although epidemiological studies in the US and Europe have confirmed that type 2 diabetes mellitus (DM) is associated with an increased risk of cardiovascular disease (CVD) events, evidence is limited in Japan. Earlier studies in Japan showed that hypertension has a major effect on atherosclerosis in relatively lean subjects, with type 2 DM contributing more to CVD events, because of a decline in blood pressure levels in both sexes and an increase in body mass index in men. Recent cohort studies in Japan using baseline assessments carried out during the 1990s have confirmed that type 2 DM is associated with an increased risk of coronary heart disease (CHD) and all types of stroke, except hemorrhagic stroke. In addition, the metabolic syndrome, a constellation of metabolic risk factors, was shown to predict CVD events in Japanese people, independent of the presence or absence of obesity. The strong association of type 2 DM with CHD (hazard ratio: 1.5-4) and ischemic stroke (hazard ratio: 2-4) events was confirmed in Japanese adults. Individuals with impaired glucose tolerance or impaired fasting glucose were also shown to have an increased risk of a CHD event, but not a stroke.