Hypertrophied palatine tonsils and adenoid is the most common disorder in pediatric otolaryngology. Especially, vegetated adenoid could induce otitis media by the obstruction of E-tube, chronic maxillary sinusitis and chronic rhinitis by the obstruction of nasopharynx and choanae with disturbance of nasal airway. This is a study on the relationship of the hypertrophied palatine tonsils and adenoid with nasal airway and chronic maxillary sinusitis in 50 cases and therapeutic effect of adenotonsillectomy in 20 cases by the followup study at the department of otolaryngology, Han Yang University Hospital. The result was as following ; 1) The sex distribution was male 28 cases(56%), female 22 cases(44%) and age distribution was from 4 to 12 year-old, average 6.8 years. 2) Size of the adenoid was divided into large, medium and small group by the extent of soft tissue shadow that occupied the nasopharyngeal air-space in the true skull lateral view. According to this method, 22 cases(44%) were in large, 22 cases(44%) in medium and 6 cases(12%) in small group. 3) Status of nasal airway was checked by the total nasal resistance(TNR) with rhinomanometric study. 4) Preoperative TNR in whole cases was average 0.820Pa/cm³sec and analyzed by the adenoid size. Large group(average 1.170), medium group(average 0.625) and small group(average 0.270). 5) Preoperative PNS X-ray showed 20 cases(40%) of sinusitis finding and this was divided and analyzed by the adenoid size. Large adenoid group occupied 10 cases(10/22, 45.4%), medium group 9 cases(9/22, 41%) and small group 1 case(1/6, 16.7%). 6) Followup study was performed in 20 cases. (1) Preoperative TNR was average 0.890 and postoperative 6mo. average 0.550, this was analyzed by the adenoid size. Large group ; from 1.350 to 0.620 Medium group ; from 0.680 to 0.492 Small group ; from 0.310 to 0.550(unit. Pa/cm³/sec). (2) By the preoperative PNS X-ray, 6 cases(30%) showed chronic maxillary sinusitis and incidence was analyzed by the adenoid size. 3 cases(3/8, 37.5%) in large group, 3 cases(3/9, 33.3%) in medium group and 0 cases in small group. (4) Folloup study on the postoperative 6 mo., improvement of chronic maxillary sinusitis was noted in 3 cases(50%). Among this, 2 cases(2/3, 66%) in large group and 1 cases(1/3, 33%) in medium group.