Aim: Knowledge about the role of the innate immune system in the pathogenesis of allergic diseases has been expanding in recent years. Defensins are antimicrobial peptides that are components of the innate immune system. Defensins have strong efficacy against bacterial, viral, and fungal infections. Moreover, they have regulatory functions in many physiologic processes such as antitumoral immunity, chemotaxis, inflammation, and wound healing. In this study, we aimed to investigate a-defensin 2 levels in the nasal fluids of children with allergic rhinitis.