Heart failure due to Chagas cardiomyopathy (HFCC) differs from failure with other etiologies because of the occurrence of intense inflammatory infiltrate and right ventricle compromise. This article investigates correlations of B-type natriuretic peptide (BNP) levels with parameters of severity in HFCC. Twenty-eight patients and 8 normal controls underwent heart catheterization and clinical and laboratory analyses. BNP levels were higher in patients with HFCC (P<.0001) and correlated with New York Heart Association (NYHA) class; right atrial pressure; wedge pressure; cardiac output; levels of serum sodium, hemoglobin, urea, and tumor necrosis factor-alpha; and ejection fraction. Interferon-gamma and transforming growth factor-beta did not correlate with BNP level. The authors conclude that BNP levels are elevated in patients experiencing HFCC, irrespective of NYHA class, and that the occurrence of HFCC correlates with severity of disease.