Obesity is a global pandemic, WHO has classify it as a Disease. Obesity attracts over 100 medical co-morbidities with an alarming reduction of life span. OSA ( Obstructive sleep apnoea )is very prevalent ( 85%) among morbidly obese patients and increase the risk of pulmonary hypertension, followed by heart failure. Bariatric surgery is currently the gold standard treatment for morbidly obese patients whom has failed the best medical treatment for weight loss. Numerous clinical evidence strongly support the safety and efficacy of bariatric surgery in significant weight loss and reversal of co- morbidities including OSA. The systematic Approach in patients undergoing bariatric surgery has now been established and has been reflected in the numerous international guidelines including the Malaysian Bariatric Expert concensus published in 2022. These stepwise approach in relation to patients with sleep Aponea and the efficacy in reduction and reversal of OSA following Bariatric surgery will be discussed.