BACKGROUND AND OBJECTIVES: A correlation between the BNP reduction ratio and prognosis could be expected to be found by evaluating the BNP reduction depending on the volume status during the early period. SUBJECTS AND METHODS: Between October 2002 and June 2004, 120 patients with acute heart failure (AHF)(<1 month) were included. The patients were divided into three groups according to their volume status, as follows. Group I: patients with clinical & radiological wet status, Group II: clinical dry & radiological wet status and Group III: clinical & radiological dry status. The blood BNP (Triage(r)) level and clinical parameters were analyzed. The bad prognostic parameters were defined as readmission due to heart failure, a major adverse cardiac event or cardiovascular death. RESULTS: The mean patient age was 68.0+/-12.7 years, and 50.0% of the subjects were male. The most frequent etiology of AHF was ischemic heart disease (35.8%). There were 61.7, 24.1 and 14.2% in Groups I, III and III, respectively. The baseline BNP level was higher in group I and II than in group III patients (I: 1540.4+/-1202.8, II: 1482.8+/-1281.6, III: 666.4+/-827.9 pg/mL, p=0.036) as was the early BNP reduction ratio (I: 69.8+/-27.1, II: 67.4+/-32.8, III: 1.3+/-144.9%, p=0.007). Sixteen (13.3%) patients had a poor prognosis. From a logistical analysis, the early BNP reduction ratio (p=0.004) and creatinine level (p=0.029) were significant predictors of the clinical outcomes. CONCLUSION: The early change in the BNP level varied depending on the degree of congestive status, and was also correlated with the level of clinical outcomes. Therefore, in our opinion, the early monitoring of the BNP level will provide significant clinical information in AHF patients.