Obesity is a risk factor for self -reported Obstructive Sleep Apnea (OSA) and makes respiratory management more difficult. The effects of bariatric surgery on OSA and Exercise Induced -bronchospasm (EIB) in obese or morbid obese subjects; both adulthood and childhood groups remain a virgin field of research worldwide. In this prospective study, 156 adult patients and 13 children with obesity were respectively evaluated before, 3, 6 and 12 months after bariatric surgery, both Sleeve gastrectomy and bypass operations. Each had Sleep tests, measures of expiratory flows, measurements of EWL corresponding to improvement of both OSA and EIB. Mean body mass index decreased from 51.2 to 34.4 kg/m2 twelve months post -surgery. EWL was gained in almost all patients with a comparable improvement in all respiratory function tests, OSA and EIB. All children showed significant improvement in Exercise induced- bronchospasm at the BMI of 30 or less. (P < 0.001) and CI (0.65), overall Mikro was 97%. Airway responsiveness, OSA and EIB markedly improved with weight loss following bariatric surgery in both adults and children obese patients. Bariatric surgery would be a definitive clue for patients suffering respiratory disorders related-obesity.