In 1997, we identified a novel peptide, catestatin (CST: bovine chromogranin A [CHGA]₃₄₄₋₃₆₄: RSMRLSFRARGYGFRGPGLQL; human CHGA₃₅₂₋₃₇₂: SSMKLSFRARGYGFRGPGPQL), which is a potent inhibitor of nicotinic-cholinergic-stimulated catecholamine secretion. CST shows characteristic inhibitory effects on nicotinic cationic (Na+, Ca²+) signal transduction, which are specific to the neuronal nicotinic receptor. Utilizing systematic polymorphism discovery at the human CHGA locus we discovered three human variants of CST: G³⁶⁴S, P³⁷⁰L, and R³⁷⁴Q that showed differential potencies towards the inhibition of catecholamine secretion. In humans, CHGA is elevated and its processing to CST is diminished in hypertension. Diminished CST is observed not only in hypertensive individuals but also in the early-normotensive offspring of patients with hypertension, suggesting that an early deficiency of CST might play a pathogenic role in the subsequent development of the disease. Consistent with human findings, prevention of endogenous CST expression by targeted ablation (knockout) of the mouse Chga locus (Chga-KO) resulted in severe hypertension that can be "rescued" specifically by replacement of the CST peptide. CST acts directly on the heart to inhibit the inotropic and lusitropic properties of the rodent heart and also acts as a potent vasodilator in rats and humans. While the G³⁶⁴S CST variant caused profound changes in human autonomic activity and seemed to reduce the risk of developing hypertension, CST replacement rescued Chga-KO mice from dampened baroreflex sensitivity. In addition, CST has been shown to induce chemotaxis and acts as an antimicrobial as well as an antimalarial peptide. The present review summarizes these multiple actions of CST.