ABSTRACTObjectivesTo determine the prevalence of positional obstructive sleep apnea (pOSA) in children undergoing adenotonsillectomy (AT) for OSA and to assess whether pOSA improves following AT.Materials and MethodsChildren with OSA diagnosed by polysomnography (PSG) at a tertiary care children's hospital were included. Data was collected on demographics, PSG parameters, and surgical management. Statistical comparisons between groups for the prevalence of pOSA were performed with the χ2 test or Fisher's exact test, for PSG parameters prior to AT with Student's t‐test or Mann–Whitney Rank Sum Test, and for PSG parameters before and after AT with paired t‐test and Wilcoxon Signed Rank Test. p < 0.05 was considered significant.ResultsOf the 1167 children (682 male, 485 female, median age = 5.7 years), 321 (28%) had pOSA. POSA children (median age = 7.4 years) were older than children with no pOSA (median = 5.2) (p ≤ 0.001). The prevalence of pOSA in the subgroups of gender and weight was not different. The prevalence of pOSA was significantly different amongst the race groups (p = 0.005). Compared with the Black/African American race, the white race had 1.4 times the odds of pOSA (95% CI, 1.07–1.98). The prevalence of pOSA was not significantly different between mild, moderate, and severe OSA groups (p = 0.7). Of the 66 POSA children who had PSG pre‐ and post‐TA, 50 (76%) had resolution of pOSA. Children older than 6 years of age and children with obesity had a higher rate of persistent pOSA (p = 0.02 and p = 0.008, respectively).ConclusionPOSA occurred frequently in OSA children undergoing AT. POSA is resolved in the majority of children after AT. Persistent pOSA was more prevalent in older and obese children. AT is used as the first‐line treatment for pOSA in children. Future studies are needed to determine the role of positional therapy and other OSA therapies in the management of persistent pOSA after AT.Level of Evidence4.