Restless legs syndrome is characterized by unpleasant, deep-seated paresthesias in the legs and sometimes the arms. These sensations occur at rest and are relieved by movement. Sleep disturbance is common. Many patients also have periodic movements of sleep. Mild symptoms of restless legs occur in up to 5% of the population. Restless legs syndrome is idiopathic in most patients, but it may be the presenting feature of iron deficiency and is also common in uremia, pregnancy, diabetes mellitus, rheumatoid arthritis, and polyneuropathy. Treatment of the underlying cause, when possible, usually relieves the symptoms. For patients with severe symptoms, levodopa, bromocriptine mesylate, opioids, carbamazepine, clonazepam, and clonidine hydrochloride have proved to be effective.