We stratified findings from the Japan Multicenter Investigation for Cardiovascular Diseases-B according to whether or not the patients had diabetes and compared the incidence of cardiac events occurring over a 3-year period between treatment with nifedipine retard and angiotensin converting enzyme (ACE) inhibitor. The primary endpoint was the overall incidence of cardiac events (cardiac death or sudden death, myocardial infarction, hospitalization for angina pectoris or heart failure, serious arrhythmia, and coronary interventions), and the secondary endpoints were a composite of other events (cerebrovascular accidents, worsening of renal dysfunction, non-cardiovascular events, and total mortality). The results showed no significant difference in the incidence of the primary endpoint between the nifedipine group (n=199) and the ACE inhibitor group (n=173) in diabetic patients: 15.08% vs. 15.03%, relative risk 1.06, p=0.838. Also in nondiabetic patients, no significant difference was observed between the former (n=629) and the latter (n=649): 13.67% vs. 12.33%, relative risk 1.04, p=0.792. Similar results were obtained for the incidence of the secondary endpoints: in diabetic patients, 5.03% vs. 5.20%, relative risk 0.89, p=0.799; in nondiabetic patients, 2.70% vs. 2.47%, relative risk 1.07, p=0.842. Achieved blood pressure levels were 138/76 and 136/77 mmHg in the nifedipine group and 140/78 and 138/79 mmHg in the ACE inhibitor group in diabetic and nondiabetic patients, respectively. This study showed that nifedipine retard was as effective as ACE inhibitors in reducing the incidence of cardiac events in extremely high-risk hypertensive patients with complications of diabetes and coronary artery disease.