Catheter ablation provides curative treatment for atrial fibrillation (AF). Data on anticoagulation after the procedure are sparse. We investigated real-life antithrombotic treatment after AF ablation and examined its adherence to current recommendations. Eight hundred forty-four patients (age 58 + or - 10 years) underwent AF ablation. Most patients had a CHADS(2) score of 0 (46%) or 1 (45%). Seven-day Holter was performed at three, six and 12 months after ablation. Decision on anticoagulation treatment was made by general practitioners and referring cardiologists in consultation with the patients. At discharge, anticoagulants were prescribed for the vast majority (94-96%) of patients. This percentage remained high at three and six months (80-90%) without differences between stroke risk groups. At 12 months, the use of anticoagulants was mainly influenced by the detection of recurrence; usage exceeded 90% in all stroke risk groups in patients with recurrences. In patients without recurrences, differences between risk groups were significant but small, ranging from 42% (CHADS(2)=0) to 62% (CHADS(2) > or = 2) (p=0.033). In multivariate analysis, the only factor independently associated with oral anticoagulation at 12 months was the detection of recurrences (odds ratio=16.2, p<0.001), whereas the effect of the CHADS(2) score was not significant (p=0.080). The effect of all other examined factors was also not significant. Contrary to current recommendations, anticoagulation after AF ablation is hardly guided by the stroke risk profile and remains high even in low-risk patients. The most important factor influencing the use of anticoagulants is the detection of recurrences during follow-up. This results in possible overtreatment of low-risk patients.