Atrial fibrillation (AF) is the most common cardiac arrhythmia, its prevalence increasing markedly with age. Atrial fibrillation is strongly associated with increased risk of morbidity, including stroke and thromboembolism. There is growing awareness of the economic burden of AF due to ageing populations and constrained public finances. A systematic review was performed (1990-2009). Cost studies for AF or atrial flutter were included; acute-onset and post-operative AF were excluded. Total, direct, and indirect costs were extracted. Of 875 records retrieved, 37 studies were included. The cost of managing individual AF patients is high. Direct-cost estimates ranged from $2000 to 14,200 per patient-year in the USA and from €450 to 3000 in Europe. This is comparable with other chronic conditions such as diabetes. The direct cost of AF represented 0.9-2.4% of the UK health-care budget in 2000 and had almost doubled over the previous 5 years. Inpatient care accounted for 50-70% of annual direct costs. In the USA, AF hospitalizations alone cost ∼$6.65 billion in 2005. In this first systematic review of the economic burden of AF, hospitalizations consistently represented the major cost driver. Costs and hospitalizations attributable to AF have increased markedly over recent decades and are expected to increase in future due to ageing populations.