During this presentation, Donald DiPette, MD, FACP, FAHA, on behalf Robert M. Carey, MD, reviews the role of the RAAS in normal blood pressure and salt and water homeostasis. In addition, Dr. DiPette discusses the role of the RAAS in the pathophysiology of cardiovascular disease, diabetes mellitus, and kidney disease, and he also details the pharmacologic inhibition/blockade of the RAAS.