Background: A robust association between brain natriuretic peptice (BNP) and N-terminal proBNP (NT-proBNP) and the short- and long-term risk of death of acute coronary syndrome has recently been demonstrated. NT-proBNP concentrations are considerably higher in most patients, probably due to decreased clearance as BNP and NT-ProBNP initially are produced in equimolar quantities. We compared the clinical efficacy of BNP and NT-proBNP in patients with acute coronary syndrome (ACS). Method: We measured serum BNP, NT-proBNP, cardiac troponin T(cTnT) and high sensitivity C-reactive protein (hsCRP) levels in 50 patients who admitted within 24 hours after chest pain. Echocardiography and Tc99m myocarial perfusion scan were performed to measure severity of coronary artery disease and left ventricular dysfunction. Results; NT-proBNP was correlated positively with BNP (r=0.961 p<0.001). NT-proBNP showed significant correlation with cTnT (r=0.454, p=0.004), hs-CRP (r=0.569, p<0.001), left ventricular ejection fraction (LVEF) (r=-0.513, p=0.001) and risk area on myocardial perfuson scan (r=0.418, p=0.03). BNP also correlated with cTnT (r=0.365, 0.02), hs-CRP (0.492, p<0.001), LVEF (r=-0.518, p=0.001), but not with risk area on perfusion scan. With the value of BNP 100 pg/ml or NT-proBNP 1000 pg/ml, diagnostic sensitivity of LVEF<45% was 70%. Conclusions: Elevated NT-proBNP is more correlated with risk parameters than BNP in ACS patients.