Insomnia is the most prevalent sleep disorders and affects severely 10% of adults worldwide. From poor sleep to insomnia, the severity of sleep disorders should be assessed clinically and by the use of validated questionnaires based on international consensual definitions. One main sign of insomnia is impaired daytime functioning. Insomnia may be treated with hypnotics only for a limited duration. Behavioural and cognitive therapies have been found efficient on chronic insomnia. Sleepiness is also a common sleep disorders due to altered sleep schedules, sleep deprivation, sleep disorders or as an adverse effect of some treatments. The risk of car accidents and the impaired quality of daytime functioning are the main consequences of sleepiness. The aim of this paper is to give some recommendations for the diagnosis and treatment of insomnia and sleepiness.