Backgroud; Brain natriuretic peptide (BNP) has emerged as a biochemical marker useful in monitoring with CHF. But, BNP response is heterogeneous during beta-blocker therapy for CHF. Also, use of beta-blockers (BB) before discharge was clinically significant in prognosis. We tested the effects of BB on BNP level and prognosis in patients with acute systolic heart failure (ASHF). Method; From Apr. 2002 to Dec. 2006, among 480 admitted ASHF patients (EF< 40%), we prospectively analyzed 210 patients underwent echocardiography on 1 to 5th day (initial) and 1 to 3 month (follow-up) and measurements of BNP (Triage짰) on admission (���24hr), early follow-up (1 to 3 month) after admission. We were divided patients to predischarge use of beta-blocker (Group I) or conventional therapy without BB (Group II).We checked clinical parameter and outcomes. Poor prognosis was defined as readmission, MI and cardiovascular death. Results: Mean age was 66.8짹15.7 and male was 48.0%. Most frequent etiology was ischemic heart disease (35.8%). NYHA class score was 3.3, initial use of ACEI was 54.7%, ARB was 29.1%, BB was 38.1 and aldactone was 69.0%. The patients with using of BB (Group 1) in predischarge medication was 38.1% (n=80) and Group II was 61.9% (n=130). There were no significant differences for clinical parameters and initial BNP levels (I: 1620.4짹980.8, II: 1422.3짹1083.6 pg/ml). There were no significant differences for echo-parameters (LV size, EF, E/E���). Mean initial systolic BP was higher in Group I than Group II (134.5짹26.8 in optimal vs. 117.9짹19.8 mmHg, p=0.021). Among BNP parameters, only significant difference was BNP reduction ratio between Group I and II (61.4짹25.7 vs.49.3짹31.2%, p=0.048) in follow-up period. Clinical outcomes were 11.4 % (n=21) in group I and 19.5% (n=41) in group II (p=0.045) but, there was no significant difference in CV death. Univariate analyses demonstrated that high plasma concentration of BNP (p =0.016), left ventricular dilation (p=0.028), and use of BB (p =0.039) at baseline were predictive of BNP reduction. Conclusions: The use of BB in predischage period potentially decreased BNP levels and improved clinical outcomes in patients with ASHF.