<b>Aim: </b>The National Hospital of Geriatrics and Gerontology (HNGG), handles tens of patients which receives an oral anti-coagulation therapy and which come from diverse provinces of the country; the study realised a clinical and socio-demographic characterization of the anticoagulated older adult population, which receives control and treatment in the external consultation of anti-coagulated persons during the period 2006-2007. <b>Methods:</b>141 older adult patients were studied, all of them anti-coagulated with warfarin during the period 2006-2007. It was performed a descriptive analysis of the demographic and clinical characteristics of all the patients, making emphasis in the causes of the anti-coagulation, comorbitities, amount of medicines used, cognitive, functional and social status, quality of the anti-coagulation, reasons for the suspension of the treatment and complications. <b>Results: </b>The average of age of the patients was of 78 years. The larger part of the population come from the cantons of San Jose province, and possess a low academic level which does not surpass the primary schooling. The Auricular Fibrillation was the main diagnostic, which justifies the anti -coagulation therapy. The most important comorbidity was the combination between the Cardiac Insufficiency and the Arterial Hypertension. The larger part of the population uses 5 or more medicines apart from the warfarin. The group of study mainly presents an adequate cognitive status, a total functional independence or a minimal dependency, and they do not present a social risk. There was a high variability in the therapeutical effects of the warfarin, which reflects in the difficulty to reach optimal levels of INR in the larger part of the cites of control and in the amount of adjustments of treatment, necessary to improve the quality of same. The main reasons to suspend the therapy of anti-coagulation were the bad adherence to the treatment, a social network not involved and the adverse effects relationed with the over-anticoagulation (minor bleedings). There was a similar incidence of minor and major bleedings (4.3%), and mortality of 1.4%. <b>Conclusion: </b>The handling of the older adult patients which receive an oral anti-coagulation therapy is of high complexity, which is reflected both in its demographic as well as clinic profile. The complications associated to the therapy, do not differ to the ones reported to an international level.

anti-coagulations; warfarin; bleeding; thrombosis