To assess the serum level of mediators and their relation with posterior ocular involvement in patients with Behcet disease (BD). This study was a prospective, institutional clinical trial including 43 patients with ocular BD. Patients were divided into two subgroups: those with active posterior segment involvement (Group A) and those with inactive ocular BD (Group B). Group A included patients with posterior uveitis (vitritis or chorioretinal involvement), while Group B included patients with no active intraocular inflammation within the last 3 months. Serum levels of interleukin (IL)-6, IL-8, tumor necrosis factor alpha (TNF-alpha), vascular endothelial growth factor (VEGF), and malondialdehyde (MDA) were measured by sandwich enzyme-linked immunosorbent assay and spectrophotometric assay and compared among the groups by independent sample t test and Mann-Whitney U-test. Serum levels of the mediators in Group A (IL-6 [23.1 pg/mL], IL-8 [161.1 pg/mL], TNF-alpha [30.5 pg/mL], VEGF [455.9 pg/mL], MDA [10.7 microm]) were found to be significantly higher than those in Group B (IL-6 [12.2 pg/mL], IL-8 [48.4 pg/mL], TNF-alpha [18.6 pg/mL], VEGF [138.0 pg/mL], MDA [5.1 microm]). This study demonstrated that increased serum levels of inflammatory mediators including IL-6, IL-8, TNF-alpha, VEGF, and MDA were possibly involved in the development of posterior uveitis in BD.