Abstract: The goal of this study was to establish whether adenotonsillectomy is effective on the severity of oxygen desaturation or improve oxygen saturation in children with sleep breathing disorders. Thirty-two children, aged 4-7 years, with clinical indication for adenotonsillectomy were enrolled in a non-controlled clinical trial. Pre- and postoperative nocturnal oxygen saturation monitoring was done and oxygen desaturation index as well as desaturation events were analyzed using Wilcoxon and paired Student’s t-tests. Snoring was the most prevalent (87.5%) complaint before operation. The study revealed a significant improvement in the postoperative oxygen desaturation index (1.60±3.22) compared with the preoperative oxygen desaturation index (3.98±4.93) (p<0.01). Oxygen desaturation events at the level of oxygen saturation 85-89% was significantly improved after operation (p<0.01). No significant differences were seen in the desaturation events at the levels of oxygen saturation lower than 85%. Nocturnal oxygen saturation improves mildly after adenotonsillectomy in children with sleep breathing disorders.