OBJECTIVES: Atrial fibrillation (AF) is the commonest cardiac arrhythmia found in clinical practice with an increasing prevalence in the aging population. Local estimates vary from 1.2 to 2.5%. The objective of our study was to evaluate the burden of AF on secondary care costs in England, which is responsible for substantial cardiovascular morbidity and mortality. METHODS: AF and stroke event and cost data captured in Hospital Episode Statistics(HES), between 2006 and 2009, was analysed to estimate the trends in hospital episodes in England. RESULTS: A total of 193,742 patients with a primary or secondary diagnosis of AF were hospitalised in 2009, representing a 19% increase in AF patients on the previous 3 years. During this period there were 239,746 hospital spells with a diagnosis of AF; a 22% increase from 2006-2009. The total inpatient cost attributable to AF increased from £353 million in 2006 to a total of £361 million in 2009. As a proportion of all admissions, AF admissions were 1.1% in 2006 to 1.2% in 2009 and represented 1,162,213 bed days occupied in 2006 versus 1,108,283 in 2009. In 2009, of the 193,742 patients with a diagnosis of AF, 5,391 subsequently had a stroke. This gives a conversion rate from AF to stroke of 3.1% of patients – up from 2.5% in 2006. During this same period, the average length of stay for the stroke patient with AF has increased from 38 days to 43 days (higher than those patients who have only had a stroke). CONCLUSIONS: Despite advances in both AF and stroke management, AF presents a significant and increasing burden on hospital care in England. New initiatives are needed to detect AF early and prevent hospital admissions or to manage AF in rapid access arrhythmia clinics where appropriate therapies to manage the rate, rhythm and cardiovascular risks can be dispensed without needing admission.