To investigate the serum level of leptin (OB) and its relationship with pro-and antiinflammatory cytokines/mediators in aggressive periodontitis (AP) patients. The study population (n= 12) comprised 6 AP patients and 6 periodontally healthy subjects (HC). The fasting venous serum samples were used to determine the OB and the cytokines/mediators belonging to the Th1/Th2/Th17 cells. The correlations among the OB and cytokines/mediators in the serum and clinical periodontal parameters were also investigated. The AP group presented significantly higher serum TGF-\beta1 and IL-2 concentrations (pg/mL) and lower IL-4, IL-5, IL-12, IL-13, and IL-17A concentrations than the HC group (P< 0.05). The ratios of OB to IL-12, IL-13, and IL-17A were lower and the ratio of OB to TGF-\beta1 was higher in the AP than in the HC group (P< 0.05). Within the limitation of the small sample size, the results of our study are important in having determined the proportional relationship of OB with the pro-and antiinflammatory cytokines'/mediators' panel in AP patients. The usage of these kits in analyzing multiple cytokines/mediators might proportionally clarify the pathogenesis of AP.