Type 2 diabetes mellitus (T2DM) is a complex heterogeneous group of metabolic disorders including hyperglycemia and impaired insulin action and/or insulin secretion. Obesity T2DM has become a serious problem in Japan as in Western countries, with over-eating and physical inactivity. Obese Asians have mild degree of adiposity, compared with Western subjects. Unlike total body fat, body fat distribution, especially excess accumulation of visceral fat, correlates with various diabetogenic, atherogenic, prothrombotic and proinflammatory metabolic abnormalities, which increase the risk of atherosclerotic cardiovascular disease (ACVD). Obese patients with T2DM have poor glycemic control with disordered eating behaviors, and complications of hypertension and dyslipidemia, leading to ACVD. The major therapies in obese T2DM, hyperinsulinemia and low insulin sensitivity, available for weight loss, especially visceral fat reduction, include caloric restriction, physical activity and behavior modification. On the other hand, the major therapies in non-obese T2DM with insufficient insulin secretion, are insulin-secretory agents and injectable insulin. For clinically meaningful prevention/reduction in the rate of future ACVD in T2DM, it may be important to stratify T2DM subjects into those with and without visceral obesity and design specific management protocols for each group.