The objective of our study was to elucidate serum levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP) in Behcet's disease (BD) patients with active and inactive period. The multicenter study included 53 patients with active (n = 28) and inactive (n = 25) BD (mean age, 34.3 +/- 9 years; 15 men and 38 women) satisfying the International Study Group criteria and 26 healthy controls (mean age, 34.4 +/- 6.1 years; seven men and 19 women) matched for age and gender from a similar ethnic background. Serum natriuretic peptides levels were determined by enzyme immunoassay kit. Mean serum ANP concentrations in the active patients (4.01 +/- 1.21 ng/ml) were significantly lower than in the healthy controls (5.76 +/- 1.99 ng/ml, p = 0.004). Mean serum BNP levels were found to be significantly higher in both the active (6.19 +/- 2.97 ng/ml) and inactive (6.49 +/- 2.88 ng/ml) BD groups compared with the control group (3.82 +/- 1.1 ng/ml, p = 0.004 and p = 0.001, respectively). Mean serum CNP concentrations in the active patients (0.49 +/- 0.12 ng/ml) were significantly lower than in the inactive patients (0.65 +/- 0.2 ng/ml, p = 0.017) and the healthy controls (0.8 +/- 0.27 ng/ml, p < 0.001). Our results suggest that changes in natriuretic peptide levels may be associated with vasculitis that play role in the etiopathogenesis of the BD.