OBJECTIVE: To determine if clinical indicators can predict the presence of moderate to severe Obstructive Sleep Apnea (OSA) after Adenotonsillectomy (T&A) in children. STUDY DESIGN: Retrospective study. SETTING: Urban Tertiary Care Pediatric Hospital. METHODS: Parents of children (<18yrs.) with OSA completed a 55-item questionnaire based on their child's symptoms at the time of preoperative polysomnography and then again at the follow up polysomnography completed 3 to 6months after T&A. MAIN OUTCOME MEASURES: 55 item questionnaire, polysomnography variables. RESULTS: 97 children were included (59 Male and 38 Female). The mean preoperative apnea hypopnea index (AHI) was 30.5+/-31.6/h and the mean postoperative AHI was 4.4+/-6.0/h. After T&A, all 97 children had reduction in AHI, and 35 (36.1%) no longer had OSA (AHI<1/h). The total symptom scores decreased from 15.8+/-9.4 to 11.3+/-8.7 after T&A (p<.0001). Fourteen symptoms highly predictive of moderate to severe OSA were identified in the univariate analysis (p<0.1). Using a cut-point of 4, this 14-item subscale illustrated an overall predictability of 72.2% (73.7% sensitivity and 70.0% specificity) for identifying children with moderate to severe OSA. CONCLUSION: A cluster of 14 clinical sleep symptoms are highly predictive of moderate to severe OSA and can serve as clinical predictor for the presence of moderate to severe OSA after T&A.