Numerous large randomized controlled trials have assessed the benefit of prophylactic anticoagulation for venous thromboembolism in selected patients. However, few trials were conducted in elderly patients, as this issue was not addressed in this specific population,or as elderly patients were excluded of these studies. Therefore, as the risk of a first episode of venous thromboembolism (in surgical and in medical setting) and the risk of a major anticoagulant-related bleeding are both increased in elderly subjects, the results of the main available studies can not be extrapolated to this population. Consequently, in practice, the balance between expected benefit and risk of prophylactic anticoagulation should be carefully assessed for each individual elderly patient taking in account the specific risk of venous thromboembolism in elderly in the absence of anticoagulation, the risk of anticoagulant related bleeding according to the type of anticoagulant treatment and the intrinsic risk of bleeding of elderly subjects and, lastly, the available guideline recommendations. In order to improve such evaluation, it is anticipated that further prophylactic studies are needed in elderly patients. In addition, the development of anticoagulation clinics and new oral anticoagulants should help to reduce anticoagulant related bleeding for an equivalent, or an increased, benefit.