Different forms of insomnia are present as symptoms of many psychiatric and other disorders. The first step for a treatment strategy is therefore a correct diagnosis. As insomnia is more common in patients with psychiatric disorders than in the general population, a careful consideration should be given, depressive and anxiety disorders should especially be carefully investigated. There are reasons to believe that even in so-called insomnia not obviously related to psychiatric disorders, stressful life situations may play a role. Therefore a co-morbidity with emotional disorders which may follow these events is worth considering. Insomnia should always be considered as pan of a sleep-wake schedule disturbance and this has an impact on the importance of the pharmacological properties of the drugs used to treat insomnia. The recent trend for more specific agents both on receptor sub-populations and on relevant sites of the GABA receptor complex will help very much in selecting the most appropriate drug for treating patients.