Continuous positive airway pressure (CPAP) is considered as the first-line treatment for OSA. Oral appliance has been shown to reduce the severity of sleep disordered breathing and leads to symptomatic improvement especially in mild to moderate OSA. The compliance with CPAP is low particularly in mild or moderate OSA patients and it is not a curative treatment of OSA. It has to be used in every night on a regular basis. Weight reduction has always been advocated in patients with OSA who are overweight and may lead to improvement in the severity of OSA. A population-based longitudinal study showed that a 10% weight loss predicted a 26% decrease in apnoea-hypopnoea index (AHI), a count of the number of upper airway obstructions per hour of sleep.