Upper airway resistance syndrome (UARS) is a condition where the apnea-hypopnea index is less than 5 and respiratory-effort related arousal index is more than 10. The clinical presentation of UARS may be the same as obstructive sleep apnea-hypopnea syndrome (OSAS); it sometimes shows up with symptoms hardly suggestive of a sleep-disordered breathing. A 17 year-old male patient had applied to a local psychiatry clinic and complained of chronic fatigue, insomnia, behavioral and academic problems and was treated for anxiety and depression. After a period of unresponsive treatment, he was sent to a sleep center for evaluation of insomnia, which turned out to be a fragmented, unrefreshing sleep episode. Polysomnographical evaluation revealed that he had UARS without OSAS. His complaints decreased dramatically after he received CPAP treatment. This case shows that UARS should be considered in young patients with functional somatic syndromes even if the clinical presentation does not apparently imply the condition.