Advances in scientific research over the last century have permitted the recognition and characterization of the structure and function of an enzymatic pathway involved in cardiovascular homeostasis and blood pressure control, namely the renin-angiotensin-aldosterone system. This system may be reversibly blocked by drugs acting at different levels: renin inhibitors, angiotensin converting enzyme inhibitors and AT1 angiotensin II receptor antagonists. Lacking clinical experience with effects of AT1 angiotensin II receptor antagonists on the cardiovascular system are practically identical to those observed with angiotensin converting enzyme inhibitors. The efficacy and safety of drugs blocking the renin-angiotensin-aldosterone system in the reduction of blood pressure, the regression of cardiovascular remodeling, the prevention of progression of diabetic nephropathy to end-stage renal failure, and the prevention of cardiovascular morbidity and mortality is well established. These hemodynamic effects of AT1 angiotensin II receptor antagonists treatment are achieved with less adverse effects than with angiotensin converting enzyme inhibitors. Furthermore, the association of angiotensin converting enzyme inhibitors and AT1 angiotensin II receptor antagonists allows a more effective renin-angiotensin-aldosterone Systems blockade and improves the hemodynamic and non-hemodynamic effects. This possibility opens up new perspectives in the treatment of cardiovascular diseases, the most common cause of death at the end of the millennium in developed countries.