OBJECTIVES/HYPOTHESIS To evaluate the association of upper airway obstruction (UAO) type and cardiopulmonary complications in children. The effect of obstruction type on quality of life and severity of obstructive symptoms were also investigated. STUDY DESIGN Cross-sectional study. METHODS A Brodsky scale and adenoid-nasopharynx ratio (ANR) were used to categorize tonsil and adenoid size, respectively. The patients were divided into four groups according to obstruction type: adenoid hypertrophy only (ANR ≥ 0.63, tonsil grade 1 or 2), adenoid and tonsil hypertrophy (ANR ≥ 0.63, tonsil grade 3 or 4), tonsillar hypertrophy only (ANR < 0.63, tonsil grade 3 or 4), and normal (ANR < 0.63, tonsil grade 1 or 2). Mean pulmonary artery pressure (MPAP), tricuspid annular plane systolic excursion (TAPSE), and right ventricle myocardial performance index (RVMPI) were evaluated for each patient. The obstructive sleep apnea questionnaire (OSA-18) and Brouilette symptom score questionnaire were completed by each child's parents. RESULTS MPAP was higher in patients with adenoid hypertrophy and adenoid and tonsil hypertrophy in comparison with the normal group. The P values were .079 and .055, respectively, when comparing TAPSE and RVMPI measurents in adenoid and tonsil hypertrophy and normal patients. A significant correlation was found between ANR and MPAP, RVMP, and TAPSE. The patients in the adenoid and tonsil hypertrophy group had the highest Brouilette symptom and OSA-18 scores. CONCLUSIONS Patients with adenoid and tonsil hypertrophy are at a higher risk for cardiopulmonary complications, poorer quality of life, and more severe UAO symptoms and should have priority for surgical treatment to prevent cardiopulmonary complications.