The term sleep-wake transition disorders refers to a group of parasomnias that occur during the transition from wakefulness to sleep or from one sleep stage to another. Rhythmic movement disorder, sleep starts, sleep talking, and nocturnal leg cramps--these four disorders belong to sleep-wake transition disorders in the International Classification of Sleep Disorders. Although these are common disorders, little attention is given to them and their mechanisms are remain unclear. The majority of patients are not so severe as to require any treatment. Their prognosis are usually well. This article describes sleep-wake transition disorders concerning the clinical features, differential diagnosis, treatment, etc.