Growth differentiation factor-15 (GDF-15), a member of the transforming growth factor-b superfamily of cytokines, plays an important role in cell growth, signal transduction, and apoptosis regulation. The aim of this study was to evaluate serum GDF-15 levels and their relationships with disease-related variables in patients with Behcet's disease (BD). Fortysix patients diagnosed with BD and 30 demographically matched healthy control subjects participated in the study. GDF-15 levels were measured in blood samples from patients and controls. The Behcet's Disease Current Activity Form (BDCAF) was used to evaluate the disease activity of BD. There were no significant differences between the two groups in C-reactive protein (CRP) level, mean erythrocyte sedimentation rate (ESR), age, body mass index, and mean GDF-15 levels (P > 0.05). Serum GDF-15 levels were positively correlated with findings for peripheral arthritis and CRP, and with BDCAF erythema nodosum, BDCAF arthralgia, and BDCAF arthritis scores. Patients with BD were divided into two groups according to the presence of peripheral arthritis; nine subjects (20%) were positive for peripheral arthritis. Serum ESR, CRP, white blood cell counts, and GDF-15 levels were significantly higher in the group that was positive for peripheral arthritis (P < 0.05). GDF-15 may play a role in the progression and pathway of Behcet's joint involvement and erythema nodosum that is independent of classic inflammatory response measures.