Older people are systematically excluded from many clinical research studies. In this review, we examine the reasons for this state of affairs and summarise the current knowledge of strategies to increase the rate of participation of older people in clinical studies. Older people want to participate in clinical research and are driven by a mixture of altruism and self-interest. They are often excluded by overt age cut-offs or covert exclusions based on co-morbidity and frailty. Other barriers to participation include communication and cognitive difficulties, transport difficulties, low income and self-imposed agism. Possible strategies to improve recruitment of older people to clinical studies include abolishing age limits, reducing exclusion criteria, and allowing sufficient study time (to recruit and deal with older patients) and money (for reimbursement of their participation costs) in study protocols. Involving older people and their attending health professionals in the design of study protocols may also be helpful. Providing transportation, easy physical access to research institutions and use of personalised and face-to-face recruitment also pay dividends. A variety of recruitment methods have been found to be effective, but tailoring the strategy to the condition and population under study is necessary. Together, these strategies should improve the representation of older people in clinical research and ensure that the evidence base is relevant and useful to all those caring for older people.