Background: Biochemical markers are useful for prediction of cardiac events in patients with acute coronary syndrome (ACS). Recently, brain natriuretic peptides (BNP) provide unique prognostic information in patients with ACS. We evaluated the associations for BNP, other biochemical markers as well as their prognostic value concerning the individual survival in ACS patients. Methods: We analyzed 466 patients from Aug. 2002 to June 2003. BNP (Triage짰, Biosite), troponin I (Bayer Dignostics), CRP (Dade-Behring) and creatinine were analyzed in blood samples obtained on admission and repeated measurement was performed in early period (< 1month). We analyzed ECG and clinical status. During the 6 months, follow-up mortality was recoded. Results: Mean age was 63.8짹12.4 and male was 59.4% (n=276). Clinical Diagnoses were distributed in unstable angina (n=214, 46.0%), non-ST MI (n=46, 9.9%) and ST elevated MI (n=205,44.1%). 6 month mortality was 18.1% (n=84). On admission, the mean BNP levels were 202.4짹389.7 pg/ml in unstable angina, 376.1짹790.7pg/ml in non-ST MI and 511.7짹937.7pg/ml ST-MI (p<0.01). The base-line level of BNP was not higher than patients who died than among those who were alive (331.8짹720.1 vs.512.1짹831.5pg/ml, p=0.054). But the BNP level of early period (<1 month) was higher than patients who died than among those who were alive (282.2짹512.1 vs. 829.5짹1097.6pg/ml, p=0.005). In a univariable analysis model, the BNP level of early period was associated with the survival (p=0.005). But, the base-line level of BNP was not associated with the survival (p=0.074). In a multivariable model, Levels of CRP, EF, creatinine clearance, and troponin I were not correlated independently with 6 month mortality, but the BNP level of early period was the marker with the strongest relation of survival (p=0.028). Conclusion: The repeated measurement of BNP, obtained in the first month after symptom onset provide predictive information to the assessment of patients with ACS.