Background: Scoliosis is defined as a three-dimensional deformity of the spine associated with lateral deviation from the normal vertical direction, and mostly with rotation of the vertebras. Although some studies have been performed on the effect of scoliosis on the respiratory system, there are still some ambiguities at issue and some results are contradictory. The aim of the present systematic review study was to help clarify the effect of scoliosis on the respiratory system and the factors affecting respiration.Methods: An electronic search was done in databases including PubMed, Web of Science, Ebsco, and Science Direct. The quality of papers was assessed using Black and Down instrument. The following keywords were used in search engines; adolescent idiopathic scoliosis, respiratory function, respiratory problem, respiratory system, ventilatory function, ventilatory problem, ventilatory system, chest wall motion, respiratory muscle, and exercise capacity. Papers in English language, subjects being over the age of 10 and suffering from adolescent idiopathic scoliosis, and no other abnormalities were among the inclusion criteria, while suffering any underlying disease was an exclusion criterion. Results: Based on the keywords used, 76 papers were found; based on the inclusion and exclusion criteria, 7 papers were approved. Five papers had dealt with pulmonary and respiratory factors, two investigating respiratory muscles, 2 examined exercise capacity, and 2 tested the chest wall motions. The score of reporting, external validity, internal validity bias, internal validity - confounding (selection bias), and power varied within 5-7, 0-2, 2-4, 0-3, and 2-5, respectively.Conclusion: Based on studies carried out so far, scoliosis affects respiratory function including respiratory volumes, chest wall motions, strength of respiratory muscles, respiratory patterns, and respiratory function during exercise. Although some studies show contradictory results, relying on the
