Purpose: Obstructive sleep apnea (0SA) has come to be the primary indication for adenotonsillar (AT) surgeries in children. Howevel postoperative respiratory complication (PoRC) is a known side effect, the correlation with 0SA and other risk factors is unclear. ln some cases, such as residual 0SA, continuous positive airway pressure (CPAP) therapy is recommended. Our aim was to investigate PoRCs, 0SA, and the efficacy of CPAP therapy in an extended indication. Methods: Prospective analysis ol 577 children who underwent polysomnography (PSG) followed by AT surgery at Heim Pal National Pediatric lnstitute, Hungary due to symptoms of sleep-related breathing disorders (SBD) between 1 January 2015 and 31 December 2018 was carried out. Afterwards a meta-analysis was conducted based on international observational studies examining PoRCs in children following AT surgery. The effectiveness of CPAP therapy prior lung transplantation in cystic fibrosis (CF) was demonstrated in a case report. Results: The incidence of PoRCs following AT surgeries is significantly higher in children with 0SA (0R: 2.24), however only in moderate (0R: 1.79) and severe (0R: 4.06) cases. Major complications did not show a higher occurrence rate in the 0SA population. While only 2% of otherwise healthy children developed PoRCs with a significantly higher registered AHI and these were mostly minor events, 58.3% of children with other comorbidities were allected and these complications were more severe. Altogetheramong children who developed PoRCs,60% were associated with severe 0SA and 70Tool them had othercomorbid-ities. On the other hand, in case of non-invasive therapy, when personalized CPAP therapy is required, improvement in FEV1 and FVC can be achieved. Conclusions: OSA significantly elevates the risk of PoRCs, but alone it does not increase the risk of major events. In mild OSA significant difference cannot be found compared to non-OSA children. The occurrence of Po RC is more sensitive to the presence of other comorbidities than to the severity of OSA. Indication of CPAP therapy can be extended due to its positive effects on lung function.  Kulcsszavak: sleep-related breathing disorders, obstructive sleep apnea, postoperative complications, adenotonsillectomy, tonsillotomy