The PFAPA syndrome is characterized by periodic fever, malaise, aphthous stomatitis, pharyngitis and cervical lymphadenitis without long-term sequelae. It has been known as one of the cause of periodic fever in children. Because there is no specific laboratory findings, the diagnosis of PFAPA syndrome is not only made by exclusion of diseases which are related to the other causes of periodic fever, but also made by a careful history and characteristic clinical manifestations. The dramatic response to the single oral dose of corticosteroid is unique to this syndrome. The PFAPA syndrome tends to be resolved without any long-term adverse sequelae. We have reported a 3 year old boy who was diagnosed as having PFAPA syndrome by episodes of periodic fever for 3 months and by excluding other febrile diseases. He was treated with oral prednisolone and his symptoms had been improved dramatically.