In the homeostasis of sodium and water metabolism, the kidney plays a pivotal role. It is the center of multiple humoral systems, such as renin angiotensin aldosterone system, arginine vasopressin, atrial natriuretic peptide, and nitric oxide, which control both systemic and renal circulation in concert. Disturbances in these systems secondary to cardiovascular compromise, especially hemodynamic insufficiency in renal circulation, lead to the accumulation of excess sodium and water, resulting in edema formation. So it is crucial to elucidate the relationship between the kidney and these vasoactive systems for the better understanding of pathophysiology of edema and volume retension.