Cancer clinical trials enable the development of novel agents for the potential benefit of cancer patients. Enrolment in a trial offers patients the chance of superior efficacy coupled to the risk of unanticipated toxicity. For trial results to be generalisable, the data need to be collected in patients' representative of the general cancer population. Socioeconomic deprivation is associated with poor cancer outcomes. In the developed world, the gap between the most and least deprived is widening. This mini-review explores the evidence regarding socioeconomics and access to cancer trials, highlighting the underrepresentation of deprived patients, and exploring reasons for this disparity.