To diagnose restless legs syndrome (RLS), start with the 4 "essential criteria": (1) a powerful urge to move the legs that is (2) rest-induced, (3) improves with activity, and (4) worsens in the evening. Carefully screen for secondary causes of RLS, including renal failure, pregnancy, iron deficiency, and medications that can cause or exacerbate symptoms. Carbidopa/levodopa is the first-line treatment for patients with intermittent symptoms of RLS; dopamine agonists are recommended for those with daily or refractory symptoms.