Sleep complaints such as difficulty initiating and maintaining sleep, restless sleep, daytime sleepiness, and bedtime anxieties are highly prevalent among children with psychiatric disorders. Subjective sleep disturbance is extremely common in pediatric depression. Early studies investigating subjective complaints of pediatric patients with depression revealed that approximately two-third of children with major depressive disorder (MDD) reported difficulty in initiating and maintaining sleep, and half reported early morning awakening. Pediatric bipolar disorder remains a somewhat poorly understood phenomenon. Anxiety is closely related to hypervigilance and hyperarousability, which inhibit sleep. Sleep disruption is a hallmark feature of both mood and anxiety disorders in children and adolescents. While the objective data is somewhat discrepant among children with mood disorders, adolescents clearly show disrupted sleep patterns, particularly in regard to REM sleep. Children and adolescents with anxiety experience significantly more disrupted sleep than their healthy peers.