Antihypertensive therapy is indicated for reducing the risk of cardiovascular morbidity and mortality that accompanies arterial hypertension. Usually, pharmacological treatment is started as monotherapy, which, if unsuccessful, is followed by sequential monotherapy, or by combination therapy. Recent data indicate that combination therapy is required in more than 50% of the hypertensive population when the goal is to reduce blood pressure to below 140/90 mm Hg. The choice and doses of drugs used in combination therapy should be such that their synergistic effect on blood pressure is maximized, the tolerability of the drugs is maintained and side-effects are minimized. The combination of a dihydropyridine calcium antagonist with a beta-blocker or an angiotensin-converting enzyme (ACE) inhibitor is one of the most commonly used combination therapies. Two randomized, double-blind, parallel-group studies compared the antihypertensive effects of the dihydropyridine, barnidipine, with the beta-blocker, atenolol (n = 247), and the ACE inhibitor, enalapril (n = 155). The efficacy and tolerability of barnidipine in combination with either atenolol or enalapril was also investigated. Monotherapy with barnidipine was as effective in reducing blood pressure as monotherapy with either atenolol or enalapril. Combining barnidipine with either atenolol or enalapril reduced blood pressure further, and significantly increased the percentage of patients attaining the required reduction in blood pressure. When patients whose blood pressure was not adequately controlled by enalapril monotherapy were switched to barnidipine monotherapy, the majority then achieved the desired reduction in blood pressure. These results indicate that if barnidipine monotherapy fails to lower blood pressure to the desired values, its combination with either a beta-blocker or an ACE inhibitor is effective and well tolerated.