OBJECTIVES: Restless legs syndrome (RLS) affects 2 to 15% of the US population. Limited data exist on patient characteristics and charges associated with emergency department (ED) visits among patients with RLS. METHODS: Data from the 2007 Healthcare Cost and Utilization Project’s Nationwide Emergency Department Sample were used. Patients were selected for inclusion if they had a diagnosis of RLS (ICD-9-CM code 333.94). Study measures included patient demographics and charges associated with the ED visit.  Study measures were reported separately for patients with a primary versus secondary RLS diagnosis. Among patients with a secondary RLS diagnosis, the most common primary diagnoses were reported.  RESULTS: A total of 6133 patients with a primary RLS diagnosis and 140,931 patients with a secondary RLS diagnosis were identified. Common primary diagnoses among patients with a secondary RLS diagnosis included respiratory symptoms (7.0%), general symptoms (4.6%), and pneumonia (3.7%). Mean (Std. Err.) age was 54.5 (0.6) years among patients with a primary diagnosis and 64.0 (0.3) years among patients with a secondary diagnosis. In both cohorts, over two-thirds of patients were female, the most common geographic regions were the South and Midwest, and Medicare was the most common primary payer (41.0% of patients with a primary diagnosis and 59.3% of patients with a secondary diagnosis). Over 90% of patients with a primary diagnosis had a routine discharge compared to only 26.6% of patients with a secondary diagnosis, and most patients with a secondary diagnosis were admitted to the facility as an inpatient. Mean (Std. Err.) charges were $816 ($48) for patients with a primary diagnosis and $2,043 ($62) for patients with a secondary diagnosis.  CONCLUSIONS: This nationally representative study suggests that patients admitted to the ED with RLS accrue substantial costs during their visit. Further research is needed to more fully assess the total economic burden of the disease.