Background and Design: Psoriasis is a chronic, T cell mediated hyperproliferative skin disease. Leptin is an adipokine that stimulates Th1 immune response while suppressing Th2 immune response. Because that leptin plays an important role in the T cell immunity, it is aimed to investigate the relation between psoriasis and leptin and whether leptin plays a role in the immunopathogenesis of psoriasis in the present study.