Objective.-To assess prescribing of anticoagulants in atrial fibrillation (AF) in the elderly, both a quantitative point of view (rate of anticoagulation) and qualitative (type of anticoagulation). Determinants of prescribing and non-prescribing were also analysed. Methods.-Prospective survey of practice, based on one clinical case and questionnaire conducted in 60 practitioners (20 cardiologists [C], 20 geriatricians [G] and 20 general practitioners [GP]). Results.-In reading the clinical case, 88.3% of physicians would have initiated a treatment; three types of treatments would have been chosen: AVK (68.3%), ODA (20.0%) and platelet antiaggregant (11.7%). Criteria taken into account to initiate anticoagulation varied according to the specialty. Cardiologists considered more the age criteria (C: 95.0%, G: 75.0%, MG: 60.0%; P < 0.05), diabetes (C: 90.0%, G: 60.0%, MG: 55.0%; P < 0.05). hypertension (C: 85.0%, G: 55.0%, MG: 60.0%; P < 0.05) and female gender (C: 80.0%, G: 35.0%, MG: 25.0%; P < 0.05). The quality of renal function was however a more secondary criteria (C: 15.0%, G: 5.0%, MG: 0.0%; P < 0.05). General practitioners considered most frequently the presence of underlying heart disease (C: 35.0%, G: 5.0%, MG: 45.0%; P < 0.05) as well as usual cardiovascular risk factors (overweight, dyslipidaemia; P < 0.05). Risk of bleeding, however, was observed by 76.7% of physicians in the clinical situation presented (C: 70.0%, G: 75.0%, MG: 85.0%; P < 0.05). Conclusion. This survey confirms that the FA remains under anticoagulated in the elderly and the barriers to the prescription of oral anticoagulation are often without rational basis. (c) 2015 Societe nationale francaise de medecine interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.