OBJECTIVES: This study estimated the economic burden of atrial fibrillation & flutter (AF) in Korea with societal perspective. METHODS: We identified patients who had at least 3 national health insurance (NHI) claims record with a primary or a secondary diagnosis of AF (ICD-10 codes: I48) in 2007. Health sector costs of the stroke were measured from the NHI claims records. Patient and family costs were estimated as transportation and cair-givers' costs  when admitting the hospitals and visiting the outpatient clinics and care-givers' cost. the costs due to productivity loss were defined as patients and caregivers productivity loss associated with outpatient visits or hospitalizations. RESULTS: A total of 56,499 AF patients were identified with prevalence for treatment of AF. The total cost of AF in the nation was estimated to be 589 billion Korean won (KRW) which included health sector cost at 41 billion KRW, patient/family cost at 8 billion KRW and cost due to productivity losses at 540 billion KRW. The per-capita cost of stroke was 10 million KRW. CONCLUSIONS: AF is not only an important risk factor for stroke but also has significant economic burden as a single disease entity. The cost due to productivity losses were identified as the largest component of the overall economic burden.