Angiotensin converting enzyme inhibitors represent a new class of agents which were designed to retain only that unique property. Because of this inhibition, administration of these agents results in the significant reduction of elevated blood pressure of various etiologies and in the amelioration of symptoms associated with congestive heart failure resistant to digitalis glycosides and diuretics. The mechanism(s) of action is not entirely certain but almost certainly resides in the inhibition of ACE. Certainly, the future will see still further advances made in this therapeutic area as well as with other inhibitors of the renin-angiotensin system.