We aimed to evaluate levels of amino-terminal pro-brain natriuretic peptid (NT-proBNP) in prediction of left ventricular ejection fraction (LVEF) in heart failure patients. Prospective study on 60 consecutive patients with symptoms and signs of heart failure was performed. Blood samples for NT-proBNP analysis was taken from all test subjects and echocardiography was also done in all of them. According to LVEF value, patients were divided into four groups; those with <or=30%, 31 to 39%, 40 to 49% and >or=50%. NT-proBNP values correlated with LVEF value. Regression analysis was used to evaluate how well NT-proBNP values predict LVEF. We used Receiver Operating Characteristic Curve calculation to evaluate diagnostic performance of NT-proBNP in estimation of LVEF. Average value of NT-proBNP in test group was 3191.69+/-642.89 pg/ml (p<0.001). Average value of NT-proBNP decreased with higher LVEF categories with significant (p<0.001) and high negative correlation (r= -0,75). Stepwise multivariate linear regression analysis showed that logarithmic value of NT-proBNP was excellent predictor of LVEF value (p<0.05). Model equation based on regression analysis was LVEF=88.645-15.311 x log (NT-proBNP). Predictive model for LVEF yielded from regression analysis had sensitivities of 98% and 81%, specificities of 20% and 90%, positive predictive values of 86% and 78% and negative predictive values of 67% and 92% for predicting patients with LVEF<50% and LVEF<40%, respectively. There was negative linear correlation between NT-proBNP and LVEF. NT-proBNP was excellent predictor of LVEF value (p<0.05).