Angiotensin converting enzyme (ACE) inhibitors were developed to prevent the generation of angiotensin II and thereby to reduce peripheral vasoconstriction. These drugs have already proven their efficacy in the management of essential hypertension as well as of various forms of secondary hypertension. When given alone or in combination with other antihypertensive agents, they allow to normalize blood pressure of almost all patients. These compounds have favorable effects on hemodynamics and regional blood flow distribution. They do not affect lipid metabolism and have usually no deleterious influence on the quality of life. In view of their efficacy and tolerability profile, ACE inhibitors are likely to become widely used as first choice antihypertensive agents.