Aspirin (acetylsalicylic acid), the most widely used antiplatelet drug, is clinically effective for the prevention of vascular ischaemic events. Very few primary or secondary prevention trials address the benefit-risk ratio of aspirin in the elderly. In secondary prevention, it is generally accepted that the beneficial effect of aspirin in the general patient population, demonstrated by randomised controlled trials, can be extrapolated to the elderly. Elderly patients are at relatively high risk for the development of vascular disease and might also be expected to derive substantial benefit from regular aspirin administration. However, there is no consensus about the definition of elderly and no specific prospective trial conducted in elderly subjects is available. Retrospective studies in the elderly found that the benefit provided by aspirin in older patients was similar or increased compared with younger individuals. In primary prevention, the potential benefit of antiplatelet agents must be balanced against the risk of bleeding, which is higher in older patients. The risk-benefit trade-off from the use of low-dose aspirin in the elderly is not yet established and caution should be exercised when using aspirin in primary prevention. In conclusion, aspirin should only be given for primary and secondary prevention in the elderly after a comprehensive evaluation of an individual patient's thrombotic and haemorrhagic risk has been conducted.