Familial mediterranean fever (FMF) is a systemic disorder characterized by recurrent attacks of fever and polyserositis. In FMF, several pro-inflammatory cytokines, such as IL-6, have been found to be elevated during the attacks. In recent years, it is shown that some proteins originated from adipose tissue play important role in inflammatory process. One of them, adiponectin decreases the expression of adhesion molecules and inhibits the attachment of active macrophages to the endothelial surface, so that it acts antiinflammatory effect. In this study, we analyzed the possible role of serum adiponectin in the pathogenesis of FMF. Thirty five patients with FMF and 13 healthy controls (5 female,8 male; mean age 22.3 ± 4.2 years) were enrolled in this study. Fifteen patients were in active stage (6 female, 9 male, mean age; 22.4 ± 4.1 years, mean disease duration 6.1±2.3 years) and 20 patients were in inactive stage (6 female,14 male, mean age;22.6 ±4.2 years, mean disease duration; 5.7 ± 1.6 years). Serum adiponectin and IL-6 levels were determined by ELISA. The mean serum adiponectin levels were 5.3 ±1.6 ng/ml in healthy controls, 55.3 ± 21.8 ng/ml in active FMF patients and 17.1 ± 4.7 ng/ml in inactive FMF patients. The mean serum IL-6 levels were 1.9 ± 0.4 ng/ml in healthy controls, 4.7 ± 1.1 ng/ml in active FMF patients and 2.9 ± 1.3 ng/ml in inactive FMF patients. Serum adiponectin levels in patients with FMF were significantly higher than in healthy controls (p < 0.001). Serum adiponectin levels were significantly high both in active FMF patients and in inactive FMF patients compared with healthy control (p < 0.001, p < 0.001 respectively). Serum IL-6 levels were significantly higher both in patients with active and inactive disease as compared with healthy controls (p < 0.01 and p < 0.05 respectively). In FMF, serum adiponectin levels were correlated with high levels of serum IL-6 in the active and inactive patients. Serum adiponectin and IL-6 levels were high during both active and inactive stages in patients with FMF.