We evaluated the clinical significance of serum N-terminal pro-brain natriuretic peptide (NT-proBNP) level in systemic sclerosis (SSc). We studied 45 SSc patients (30 with limited and 15 with diffuse cutaneous SSc) of mean age +/- SD 47.1 +/- 12.9 years, mean duration of disease 10.2 +/- 6.0 years, and 45 age- and sex-matched healthy controls. Pulmonary artery pressure was measured by echocardiography. Lung involvement was evaluated by pulmonary function testing and by using high-resolution computed tomography scores. Serum NT-proBNP levels were measured using a sandwich electrochemiluminescent immunoassay. Serum NT-proBNP levels were significantly higher in patients with SSc compared to healthy controls. When the patients were divided into clinical subsets, serum NT-proBNP was higher in diffuse SSc than in limited SSc. Serum NT-proBNP levels were found to be positively correlated with age, skin thickness score, and systolic pulmonary artery pressure and negatively correlated with percentage of carbon monoxide diffusion capacity (DLco). Multivariate analysis showed that serum NT-proBNP levels were positively correlated with age (p = 0.010), skin thickness score (p = 0.000), and blood pressure (p = 0.021) and negatively correlated with %DLco (p = 0.016). Fifty-seven percent of the variation in log (proBNP) can be explained by the multivariate model (R (2) = 0.57). Serum NT-proBNP levels were higher in SSc patients (particularly the diffuse subset) than in healthy controls and were found to be correlated with skin thickness and %DLco. We conclude that serum NT-proBNP may be a biologic marker of skin fibrosis and pulmonary vascular involvement in SSc.