Objective. Although oral anticoagulation (OAC) has proved beneficial for patients with atrial fibrillation (AF) and embolic risk factors, it is still underused. The objective of this study was to evaluate the adequacy of anticoagulation therapy in patients with AF followed up in a private clinic specialized in cardiology, in accordance with the American and European societies of cardiology guidelines/2006 and with the Sociedade Brasileira de Cardiologia (Brazilian Society of Cardiology -SBC) guidelines/2003. MethOds. Between November 2005 and August 2006, 7,486 electrocardiograms were evaluated and 53 patients with AF diagnosis and complete detailed information in medical records on embolic risk factors and oral anticoagulation treatment were selected. Results. Among the 53 patients included (68±16 years; 29 men -55%), 25 (48%) had hypertension, 20 (38%) heart failure and 3 (6%) diabetes mellitus. Among the 15 patients with high embolic risk, 13 (86%) were using OAC. In accordance with the American and European guidelines: 32 (60%) patients were Class I, 17 (32%) Class IIa, 1 (2%) Class IIb and 3 (6%) Class III. Treatment was adequate in 21 (66%) Class I patients and 13 (76%) Class IIa. In this subgroup, anticoagulation therapy was being used in 7/19 (37%) patients ≥ 75 years compared to 22/30 (73%) younger (p=0.016). Among the 3 patients within Class III, 1 was incorrectly on OAC. According to Brazilian guidelines, 33 (62%) were on correctly indicated antithrombotic therapy. There was no difference in the appropriate prescription of oral anticoagulants, comparing Brazilian and American/European guidelines (55% vs. 55%). cOnclusiOn. Anticoagulant therapy is being adequately prescribed for the majority of AF patients, although this index is still far from ideal, especially in a cardiology clinic. This is even more critical in the group of elder patients.