History taking, digital examination, posterior rhinoscopy or cephalometric radiologic examination are used for assessing the adenoid and the nasopharyngeal airway in children. But it is difficult to know the nasopharyngeal condition objectively. Magnetic resonance imaging(MRI) is a reliable method to delineate the soft tissue structures and can show the cross-sectional condition of the nasopharynx. The authors used magnetic resonance imaging to evaluate the adenoid and the nasopharyngeal airway and correleated the patient's symptoms. We scanned 245 children and obtained 6 parameters : The adenoid area, the nasopharyngeal airway area, the nasopharyngeal area, the ratio between the adenoid and the nasopharyngeal airway area, the ratio between the adenoid and the nasopharyngeal area, the adenoidonasopharyngeal ratio of Fujioka. We found that the ratio between the adenoid and the nasopharyngeal airway area is the most significant parameter for assessing the nasopharyngeal airway.