Exact estimation of pharyngeal tonsil is the most important factor in qualification to adenoidectomy in hypertrophy of adenoid and chronic inflammation of the nasal part of the throat. Well-known methods like posterior rhinoscopy and palpation of the adenoid are difficult and sometimes differ from the result of operation. Fiber optic techniques create possibilities of noninvasive examination of adenoids and may explain criteria of qualification to adenoidectomy. The aims of the work were to study the anatomy of the nasal part of the throat in children in different age groups and the objective estimation of adenoid as indication for adenoidectomy. ENT examination, fiber optic nasopharyngoscopy, lateral X-ray of the nasopharynx, rhinomanometry, tympanometry and audiometry were performed. The test group consisted of 60 children, qualified for adenoidectomy, in age groups 2–4, 4–8 and 8–12 years. The comparative group was composed of 15 children without symptoms of obturation in nasopharynx, treated because of different diseases, and divided into same age groups. A method of objective estimation of nasopharynx based on computerized planimetry, called obturation index (OI), has been worked out. The results indicate that fiber optic examination is more precise than posterior rhinoscopy and palpation and correlates with results of the X-ray and rhinomanometry so that it may replace these examinations. OI over 60% seems to be pathological especially in children between 4 and 8 years. Hypertrophy of adenoid influence on the state of hearing organ is most significant.