SUMMARYThe aim of this study was to determine how body mass index (BMI) influences the N-terminal pro-B-type natriuretic peptide (NT-proBNP) level in patients with significant coronary artery disease (CAD).A total of 348 patients (61.5 ± 9.2 years, male 67.5%) who had normal left ventricular systolic function were enrolled. All patients underwent percutaneous coronary intervention. We excluded patients with acute myocardial infarction, chronic heart failure, or renal dysfunction. Baseline NT-proBNP level was measured on admission. All underwent follow-up (F-U) coronary angiography (CAG) and the F-U NT-proBNP level was measured before F-U CAG. The patients were divided into two groups: an NT-proBNP < 100 pg/ mL group (group I, n = 228) and an NT-proBNP > 200 pg/mL group (group II, n = 120). BMI was significantly higher in group I than that in group II (26.5 ± 2.2 versus 22.9 ± 2.5 kg/m 2 , P < 0.001). The level of NT-proBNP was negatively correlated with BMI and the levels of hemoglobin and apolipoprotein A1, and positively correlated with age, lipoprotein (a), and the Gensini score. In multivariate analysis, BMI was significantly related to a low NT-proBNP level in patients with CAD (odds ratio, 6.83; 95% confidence interval, 2.67-17.47; P < 0.001).The NT-proBNP level was not elevated in patients with a high BMI despite having significant CAD, and BMI was significantly related to a low NT-proBNP level in patients with significant CAD. (Int Heart J 2008; 49: 403-412)