Abstract: AIM: To investigate the levels of the kaliuretic peptide (KP), atrial natriuretic peptide (ANP) and endothelin (ET) in elderly patients with congestive heart failure (CHF) and to evaluate the beneficial effects of angiotensin receptor blockers on the above variables. METHODS: Ninety-four elderly patients with CHF were randomly divided into two groups: routine group was treated with routine drugs (nitrate-like drugs, diuretics and digoxins) (n=47) and candesartan group treated with angiotensin receptor blocker candesartan (n=47). Plasma levels of KP, ANP and ET were detected by radioimmunoassay before and after treatment in all patients and in the control group of 34 healthy subjects. Left ventricular ejection fraction (LVEF) was also measured by nuclear ventricular imaging. RESULTS: Compared with those in the control group, plasma levels of KP, ANP and ET in elderly patients with CHF were much higher at each time point during the study. There was a significant negative correlation between KP and ANP and LVEF 12 weeks after treatment, and there were significant differences in KP levels within NYHA II, III and IV in elderly CHF patients. KP and ANP levels decreased more significantly in the candesartan group than in the routine group (P<0.05). CONCLUSION: KP and ANP may play an important role in the pathogenesis of CHF. Candesartan suppresses the overactivation of the neurohumoral system and renin-angiotensin-aldosterone system in elderly patients with CHF.