The major risk factors of arteriosclerosis obliterans(ASO) in diabetic patients are age, male gender, smoking, poor glycemic control, hypertension, and dyslipidemia. Thus, to prevent the development and progression of ASO, intensive intervention in the risk factors should be required. HOPE study reported that treatment of ACE-inhibitor in the patients with ASO for 5 years clearly decreased the relative risk for incidence of cardiovascular events comparing with the placebo group. Furthermore, UKPDS Group demonstrated that the adjusted odds ratios to the development of ASO for each 1% HbA1c increase and each 10 mmHg systolic blood pressure increase were respectively 1.28 and 1.25 from multivariate analysis. However, optimal levels of HbA1c and blood pressure for prevention of ASO still have not been suggested. Therefore, large-scale intervention trial in Japanese diabetic subjects should be needed.