Treatment resistance is an important issue in patients with depressive disorder and nearly a third of patients may not reach remission despite multiple drug trials. Obstructive sleep apnea syndrome (OSAS) is a common sleep disorder in which daytime sleepiness, sleep disturbance, fatigue, decreased quality of life, memory problems, irritability are frequently observed. Polysomnography is required to confirm the diagnosis of OSAS We aim to present a case with treatment resistant depressive symptoms. In his detailed assessment we observed that his complaints were related to OSAS and he was successfully treated with bi-level positive airway pressure (BPAP). Particular attention shoul be paid to OSAS symptoms in patients with treatment resistant depression.