In order to reduce risk of cardiovascular diseases (CVDs) in patients with type 2 diabetes, it has been suggested that multifactorial intervention in blood glucose (BG), blood pressure (BP) and lipids could be effective, while blood glucose lowering alone may not be sufficient. It has not been fully evaluated, however, how the ideal and feasible targeted levels of the parameters should be set and actually achieved. In J-DOIT3, Japan Diabetes Optimal Intervention Trial for 3 major risk factors of cardiovascular diseases, we intended to examine the hypothesis that stricter control of BG, BP and lipids, compared to conventional control recommended in the diabetes guideline in Japan, could efficiently and safely reduce the risk of CVDs. Among 81 participating hospitals all over Japan, we screened type 2 diabetic patients with hypertension and/or dyslipidemia, followed by random allocation into two groups: namely the intensive therapy group (ITG) and the conventional therapy group (CTG). The target of HbA1c was < 6.2% in the ITG and <6.9% in the CTG, while that of BP was < 120/75 mmHg and < 130/80 mmHg, and targeted LDL cholesterol, < 80 mg/dL (< 70 mg/dL in the presence of CVD history) and < 120 mg/dL (< 100 mg/dL). We recruited 2542 patients, 1271 of whom were allocated into the ITG, and the other 1271 subjects into the CTG. The trial is now still under way, and actually incidence of severe hypoglycemia in J-DOIT3 has been extremely low, compared to the previous studies. Thus, J-DOIT3 is expected to provide evidence that multifactorial intervention including blood glucose control with a stricter target is indeed beneficial to prevent cardiovascular complications of patients with type 2 diabetes in this region.