PURPOSE: Little is known about the influence of socioeconomic factors on patient access to cancer trials. Differences should be considered to ensure generalizability of trial results and equality of access. METHODS: Phase I trials unit referrals at our center over 5 years, from 2007 to 2012, were reviewed. Socioeconomic status was defined by the Index of Multiple Deprivation (IMD; 1, least deprived; 5, most deprived). Multivariate analysis was performed comparing incident cancer cases with referred patients and those ultimately enrolled onto a trial. RESULTS: Four hundred thirty patients were referred (median age, 62 years). Compared with 10,784 incident cases, referral was less likely for patients in the more-deprived quintiles compared with the least deprived (IMD 5: odds ratio [OR], 0.53; 95% CI, 0.38 to 0.74). Once reviewed in the unit, enrollment onto a trial was not affected (IMD 5: OR, 0.81; 95% CI, 0.40 to 1.63). Ethnicity analysis showed the nonwhite population was less likely to be recruited (OR, 0.48; 95% CI, 0.26 to 0.88). This relationship was lost with adjustment for age, sex, cancer type, and deprivation index. CONCLUSION: We show for the first time to our knowledge that socioeconomic status affects early-phase cancer trial referrals. The least-deprived patients are almost twice as likely to be referred compared with the most deprived. This may be because more-deprived patients are less suitable for a trial-as a result of comorbidities, for example-or because of inequalities that could be addressed by patient or referrer education. Once reviewed at the unit, enrollment onto a trial is not affected by deprivation.