Kerion celsi is an inflammatory form of tinea capitis. It is a kind of id reaction due to immunologic reaction to circulate antibodies or activate T lymphocytes that are directed against dermatophytes. In kerion celsi early diagnosis is important because a delay in treatment can lead to bacterial superinfection, resulting cicatrization and permenant alopecia. Mean Platelet volume (MPV) is an easily available parameter in hemogram related with thrombocyte activation and inflammation. It acts as a negative or positive acute phase reactant in different inflammatory conditions. This study evaluated MPV in kerion which has never been reported before. It is a retrospective study of 47 patients and 47 heathy controls. MPV and the other laboratory tests were recorded.MPV levels in children with kerion celsi were investigated.