Background: Vitiligo is a pigmentation disorder which is associated with increased expression of inflammatory cytokines in the skin and blood. Interleukin-17 is a cytokine which exerts strong proinflammatory activates and although considered a major mediator of tissue inflammation in several models of inflammatory diseases, its role in vitiligo is still under investigation. Aim of the work: The aim of this work was to study the role IL-17 in the pathogenesis of vitiligo by investigating its serum level and its gene expression in lesional skin in patients with vitiligo and compared with controls. Methods: Thirty patients with vitiligo and 15 controls were enrolled in the study. Serum IL-17 level was measured by enzyme linked immunosorbent assay (ELIZA) and its skin expression was measured by reverse transcriptase-polymerase chain reaction (RT-PCR) in both groups. Their correlation with age, gender, disease duration, disease activity, type of vitiligo and family history were assessed. Results: A significant increase was found in levels of both serum IL-17 and skin mRNA expression in vitiligo patients compared with controls (p < 0.001). In vitiligo patients, there was a significant positive correlation between serum levels of IL-17 and skin levels of IL-17 mRNA expression (r= 0.978, p < 0.001), and both of them were significantly higher in active than stable vitiligo (p