Restless legs syndrome (RLS) is a neurologic movement disorder that is often associated with a sleep complaint. Patients with RLS have an irresistible urge to move their legs, which is usually due to disagreeable sensations that are worse during periods of inactivity and often interfere with sleep. It is estimated that between 2 and 15 percent of the population may experience symptoms of RLS. Primary RLS likely has a genetic origin. Secondary causes of RLS include iron deficiency, neurologic lesions, pregnancy and uremia. RLS also may occur secondarily to the use of certain medications. The diagnosis of RLS is based primarily on the patient's history. A list of questions that may be used as a basis to assess the likelihood of RLS is included in this article. Pharmacologic treatment of RLS includes dopaminergic agents, opioids, benzodiazepines and anticonvulsants. The primary care physician plays a central role in the diagnosis and management of RLS.