Primary insomnia is a dyssomnia characterized by a complaint of difficulty in initiating or maintaining sleep and the absence of restorative sleep that lasts for at least 1 month. The polysomnographic test shows alterations in the induction, continuity and structure of sleep. Primary insomnia typically begins in young adulthood, has a chronic course, and it is more prevalent among women. Its prevalence among patients with chronic insomnia ranges from 12.5% to 22.2%. Primary insomnia must be distinguished from insomnia related to inadequate sleep hygiene or another mental disorder, such as generalized anxiety disorder or a mood disorder. The treatment of primary insomnia consists of nonpharmacological strategies (sleep hygiene, behavior-cognitive therapy) and sleep-promoting medication (e.g. hypnotics). Few differences exist between benzodiazepines, zopiclone and zolpidem in terms of effectiveness in inducing and maintaining sleep. However, in contrast to benzodiazepines, zolpidem and zopiclone do not suppress slow-wave sleep. Rebound insomnia and drug addiction are uncommon.