This study aimed to look for the discrepancy between the laboratory investigation (determination of serum NT-proBNP), electrophysiological assessment (echocardiogram and Doppler study) and clinical assessment of known cases of congestive heart failure.This study conducted in the college teaching hospital from January to October 2011. This study is a cross-sectional in a cohort of patients with heart failure. Known cases of congestive heart failure and healthy subjects served as control group were enrolled in this study. Patients were assessed clinically according to the New York Heart Association (NYHA) functional classification, echocardiography by ejection fraction and laboratory by determination of NT-proBNP).Student's "t" test (one paired, two tailed) and simple correlation test were used in data analysis. The results of 169 patients enrolled in this study showed that serum levels of NT-proBNP did not match the NYHA functional classification of heart failure. Serum NT-proBNP was significantly inversed-correlated (r = -0.339, p < 0.001) with the serum ejection fraction and inconsistently related to the E/A ratio assessed by Doppler study. It concludes that serum NT-proBNP level is well correlated with ejection fraction and not well matched the functional disabilities of longstanding heart failure.