OBJECTIVE: To correlate the serum levels of B type natriuretic peptide and the N-terminal fraction of the pro-B type natriuretic peptide, as well as to analyze the influence of age, obesity, renal failure, left ventricle ejection fraction, diastolic dysfunction, and anemia on serum levels of both markers. METHODS: An observational study in which the agreement was compared between these markers in consecutive samples of 138 patients. For the correlation, Pearson’s test was used, and p