The Japan Multicenter Investigation for Cardiovascular Diseases-B was performed to investigate whether nifedipine retard treatment was associated with a significantly higher incidence of cardiac events than angiotensin converting enzyme inhibitor treatment in Japanese patients. The study used a prospective, randomized, open, blinded endpoint (PROBE) design. Patients were enrolled at 354 Japanese hospitals specializing in cardiovascular disease. The subjects were 1,650 outpatients aged under 75 years who had diagnoses of both hypertension and coronary artery disease. There were 828 patients subjected to intention-to-treat analysis in the nifedipine retard group and 822 patients in the angiotensin converting enzyme inhibitor group. The patients were randomized to 3 years of treatment with either nifedipine retard or angiotensin converting enzyme 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). The primary endpoint occurred in 116 patients (14.0%) from the nifedipine retard group and 106 patients (12.9%) from the angiotensin converting enzyme inhibitor group (relative risk, 1.05; 95% confidence interval, 0.81-1.37; p = 0.75). In the Kaplan-Meier estimates, there were no significant differences between the two groups (log-rank test: p = 0.86). The incidence of cardiac events and mortality did not differ between the nifedipine retard and angiotensin converting enzyme inhibitor therapies. Nifedipine retard seems to be as effective as angiotensin converting enzyme inhibitors in reducing the incidence of cardiac events and mortality.