The renin–angiotensin–aldosterone system (RAAS) is a key mediator of blood pressure (BP) and volume regulation in both normotensive and hypertensive persons. Stimulation of RAAS also contributes to hypertension-related target organ damage. The renin–angiotensinogen reaction is the first and rate-limiting step in the generation of angiotensin II (Ang II) and has been a target of antihypertensive drug development for decades. Aliskiren is the first in a new class of orally effective direct renin inhibitors (DRIs) and is approved for the treatment of hypertension in humans. It effectively reduces BP in the general population of hypertensive patients and has a tolerability and safety profile similar to placebo. Aliskiren has favorable effects on vascular inflammation and remodeling, on neurohumoral mediators of various forms of cardiovascular disease, including heart failure, and on proteinuria in diabetic patients. Additional outcome trials are needed to establish the role of this novel class of antihypertensive medication in preventing cardiovascular disease morbidity and mortality.