Children with obstructive sleep apnea (OSA) show symptoms such as snoring, sleep apnea, and oral breathing. The diagnosis of the disease can be made through polysomnography and as the most common causes are tonsillar and adenoid hypertrophy, tonsillectomy and adenoidectomy (T et A) are considered as initial treatment. OSA is an increasingly recognized problem in children with Down syndrome, who are more prone to facial hypoplasia, hypoplasia of the mandible, and have a large tongue. In OSA Down syndrome patients, T et A can be performed if tonsillar hypertrophy is present. However, because these patients have underlying diseases (atlatoaxial unstability, airway problem, heart problem, endocrine problem), general anesthesia may be difficult and cervical extension may be limited during the operation. We describe a case of 10-year-old child with Down syndrome and OSA, who underwent T et A under general anesthesia through multidisciplinary care.