Chronic heart failure (CHF) is a clinical complex showing end -stage of several cardiovascular disorders. Patients with CHF are disclosed to both of high mortality and high morbidity. Most of them repeat frequently the hospitalization. In CHF patients, neurohumoral factors such as renin -angiotensin -aldosterone systems (RAAS) are enhanced, and they result in high level of angiotensin, aldosterone and catecholamine in the cardiovascular tissue. Most of the hormones are known as cardiotoxic agent. The activated RAAS is closely linked with progression of cardiac remodeling. Thus, ACE inhibitor can block this linkage. Recently, several randomized controlled trials in large scale reveal that the ACE inhibitor is a beneficial tool for not only CHF therapy but also CHF prevention. The blocking effects by ACE inhibitor are playing a crucial role in releasing the CHF patients from several burdens.