It was established that renin-angiotensin-aldosterone system (RAAS) controls blood pressure and body fluids peripherally. However, it was intriguing that central injection of angiotensin II (Ang II) also boosted the blood pressure and evoked thirst sensation suggesting that elements of the RAAS are also expressed in the brain. The role of the RAAS in hypertension and emotional disorders is well established. Evidence points to an association between elevated RAAS activity and depression, partly through the induction of neuroinflammation, and oxidative stress, and suppression of BDNF. Therefore, blocking the RAAS provides a theoretical basis for future treatment of depression.