background Most individuals with mental disorders complain about the problems they experience with sleeping and waking. It is becoming evident that careful diagnosis of sleep-wake disorders is of great importance for the prevention and treatment of mental disorders. Since the introduction of the dsm-iv, clinical scientific research has provided important new insights in this field. aim To find out whether the new classification of sleep-wake disorders in dsm-5 is likely to improve the diagnosis of disorders of this type. method We discuss the main changes in the dsm-5 classification of sleep- wake disorders, comparing the new version with the version in dsm-iv. results Because considerable attention is being given to the symptom-orientated and dimensional approach, the classification of sleep-wake disorders in the DSM-5 is closer to current psychiatric practice and it does justice to the current scientific insights into the dimensional nature of psychiatric disorders. conclusion The dsm-5 classification takes recent scientific insights into account and might help to improve the diagnosis of sleep-wake disorders in psychiatry.