In this prospective study, fiberoptic examinations of the nasal cavity and nasopharynx were performed in 162 children with snoring and compared with similar examinations performed in 211 children without snoring. Our study aimed to determine a correlation between snoring and measured parameters of nasal and nasopharyngeal anatomy including the size of the adenoid tissue. Results have confirmed significant evidence that adenoid hyperplasia is the commonest etiologic factor in children with snoring (p < .001). In addition, an important statistical relevance of mouth breathing in snoring was demonstrated (p < .001). It seemed that mouth breathing is a basic condition in children's snoring. It is essential to both confirm that mouth breathing occurs, and then, to institute an appropriate treatment as a therapeutic approach for children with snoring. The introduction of the flexible fiberscope in the fields of pediatric examination of the nasal cavity and nasopharynx has proved to be of great clinical value.