Objective: to investigate and demonstrate changes in cardiopulmonary functions pre & post-operative in children suffering breathing difficulties due to adenotonsillar hypertrophy and scheduled for adenoteonsillectomy. Patients and methods: This study was carried out on 80 children from both genders with ages ranging from 3-14 years suffered from adenotonsillar hypertrophy complicated with obstructive sleep apnea [OSA), and upper airway resistance syndrome were scheduled for adenotonsillectomy. All cases followed up for 3 months after operation. Results: As regarding to echocardiography & Sp_O2 was the same at pre & post-operative assessment. The snoring, difficult breathing, adenoid hypertrophy &nocturnal enuresis showed statistically significant decrease postoperatively [P <0.001). While the appetite, social activity showed statistically significant increase in patient postoperatively [P<0.001). Conclusion: Adenotonsillectomy may have serious impact on improving some annoying manifestations like loss of appetite, nocturnal enuresis or even on affecting the daily normal life activities of a large scale of pediatric population.