Sleep disorders in central or peripheral nervous system diseases frequently occur, but they often are neglected in diagnosis and therapy. During the last 20 years, sleep medicine has obtained more and more importance. It is possible to draw conclusions about the topical organization of sleep-wake-regulation by investigating of certain diseases. In the following survey the most important clinical pictures in neurology are described in consideration of an affected sleep. Typical symptoms and polysomnographic findings as well as recommendations for therapy are demonstrated.