The objective of this study was to assess the role of resistin, a proinflammatory cytokine potentially involved in Behçet's disease (BD), and to determine its relationship with tumor necrosis factor α (TNF-α), another important inflammatory cytokine known to be involved in BD. Forty-five persons diagnosed with BD were enrolled into this study, 25 of whom were being followed or had recently been diagnosed with clinically active BD, whereas the remaining 20 were previously diagnosed and had clinically inactive BD for the previous 3 months. Thirty persons were recruited as a healthy control group. Patients' C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), resistin, and TNF-α levels were determined with enzyme-linked immunosorbent assay (ELISA). Resistin and TNF-α levels were significantly higher in patients with BD (p < 0.05 and p < 0.05) than in the control group. The major interest of this study was to investigate the role of resistin in patients with BD. An elevated resistin level was associated with activation of BD. Elevated TNF-α and resistin levels could be determined simultaneously, and the presence of these two cytokines together suggests that resistin plays an important role in the pathogenesis and activation of BD.