Background: The level of N-terminal pro-B-type-natriuretic peptide (NT-proBNP) is a strong predictor of mortality among patients with acute coronary syndrome. The aim of this study is to assess the effect of more intensive medical therapy on clinical outcome in patients with left ventricular (LV) dysfunction complicated acute myocardial infarction (AMI), who have high NT-proBNP. Methods: A total of 68 patients (63.4짹11.1 years, male 85.7%) with LV dysfunction [LV ejection fraction (LVEF) < 45%] complicated AMI who underwent coronary intervention (PCI) were enrolled. The patients were divided into three groups: NT-proBNP > 1000 pg/mL and combination with three drugs (group I, n=25), NT-proBNP > 1000 pg/mL and combination with two drugs (group II, n=25), NT-proBNP < 1000 pg/mL and two drugs (group III, n=18) [three drugs: beta blocker and angiotensin converting enzyme inhibitor (ACEI) and statin, two drugs: ACEI and statin]. Results: The mean value of baseline NT-proBNP was 4061.6짹2539.5 pg/mL, 4236.8짹2123.1 pg/mL, and 334.7짹293.8 pg/mL (Group I, II, III, respectively, p<0.001 between group I, or group II and group III). The baseline characteristics including baseline LVEF and use of other medications between the groups were similar. At 6-month after PCI, the LVEF was improved significantly in Group I and III (39.1 % to 51.5%, p<0.001; 39.4% to 51.8%, p=0.002). Follow –up (F-U) LVEF was significantly higher in group I or III compared with group II (51.5% vs. 40.7%, p=0.006; 51.8% vs. 40.7%, p=0.021). The result on major adverse cardiovascular events (MACE) showed no significant differences between the groups (reinfarction: 1 patient, 1 patient, 0 patient; target lesion revascularization: 1 patient, 4 patients, 1 patients; repeat PCI: 4 patients, 6 patients, 3 patients; Group I, II, III, respectively). In multivariate analysis, the level of baseline NT-proBNP and numbers of combination drug were an independent predictor for improvement of LVEF (odds ratio, 9.95; 95% CI 2.9-33.1, p=0.010; odds ratio, 5.56; 95% CI 1.41-28.3, p=0.029). Conclusion: More intensive medical therapy improved LV function in patients with AMI who have high NT-proBNP despite no risk reduction of MACE.