Calcium (Ca(++)) plays an essential role in many cardiovascular physiologic processes. Electrophysiologic properties of the sinus and atrioventricular nodes greatly depend on Ca(++) ion influx. Also, Ca(++) is the main link for excitation-contraction coupling of the myocardium. Ca(++) channel blockers are a group of heterogeneous compounds that block the ionic influx of Ca(++) into the myocardial and vascular smooth muscle cells. Because Ca(++) plays a central role, it is not surprising that Ca(++) channel blockers can produce profound alterations in cardiovascular functions. Recently several studies have shown these agents to be useful in the treatment of supraventricular tachyarrhythmia, variant angina, chronic stable angina and hypertrophic cardiomyopathy. In the future they may be found useful in preserving myocardium during cardiopulmonary bypass, in limiting infarct size and in the treatment of hypertension and congestive heart failure.