Restless legs syndrome (RLS) is a sensorimotor disorder characterised by an irresistible urge to move the legs, often accompanied by uncomfortable sensations in the legs or, less frequently, in other body parts. These sensations are relieved by movement, and are worse in the evening, or at night and when at rest. The diagnosis of RLS is based on the revised RLS criteria developed by the International Restless Legs Syndrome Study Group (IRLSSG). Although RLS has traditionally been considered a disorder of middle to older age, several case reports have shown that it may occur in childhood. Since children may report RLS symptoms differently than adults, in part because of their limited ability to describe RLS sensations, the IRLSSG has proposed a set of criteria specific for childhood diagnosis. Polysomnographically, RLS may be associated with periodic limb movements in sleep (PLMS) in about 80% of patients, both in adults and in children.