Obstructive sleep apnea syndrome (OSAS) is characterized by repetitive episodes of upper airway obstruction which occurs during sleep and usually associated with a reduction in oxygen saturation, and it is one of the common health problems with significant mortality and morbidity. It is very well-known that OSAS alters the serum levels of several hormones by the effect of hypoxia on central neurotransmitters that causes changes in the hypothalamic-pituitary-adrenal axis (HPA) in relation with sleep fragmentation. Growth hormone secretion (GH) is affected by several factors such as age, sex, obesity, body composition and sleep quality. Also, the oxygen content of the inhaled air affects the secretion of GH. On the other hand, intermittent hypoxemia increases GH secretion. In this study, we aimed to examine the serum level of GH in patients with OSAS.