Obstructive sleep apnea (OSA) is an increasingly prevalent condition that is characterized by repetitive upper airway obstructions. OSA has been independently associated with insulin resistance, suggesting that OSA may contribute to the development of type 2 diabetes and the metabolic syndrome. Recently, postprandial glucose and lipid have been reported as excellent predictors for mortality and cardiovascular risk. However, the association between postprandial glucose, lipid metabolism and OSA are not clear. In addition, humoral factors such as ghrelin and leptin are associated with obesity and OSA, but postprandial changes of which in patients with OSA are not well known. The aim of present study is to examine postprandial glucose and lipid metabolism, humoral factors in OSA before and after 3 months of continuous positive airway pressure (CPAP) treatment.