Objectives: To assess whether the change from the Undergraduate Medical and Health Sciences Admissions Test (UMAT; 1991–2019) to the University Clinical Aptitude Test (UCAT) for the 2020 New South Wales undergraduate medical degree intake was associated with changes in the impact of sex, socio-economic status and remoteness of residence, and professional coaching upon selection for interview. Design, setting, participants: Cross-sectional study of applicants for the three NSW undergraduate medical programs for entry in 2019 (4114 applicants) or 2020 (4270); 703 people applied for both intakes. Applicants selected for interview were surveyed about whether they had received professional coaching for the selection test. Main outcome measures: Scores on the three sections of the UMAT (2019 entry cohort) and the five subtests of the UCAT (2020 entry); total UMAT and UCAT scores. Results: Mean scores for UMAT 1 and 3 and for all four UCAT cognitive subtests were higher for men than women; the differences were statistically significant after adjusting for age, socio-economic status, and remoteness. The effect size for sex was 0.24 (95% CI, 0.18–0.30) for UMAT total score, 0.38 (95% CI, 0.32–0.44) for UCAT total score. For the 2020 intake, 2303 of 4270 applicants (53.9%) and 476 of 1074 interviewees (44.3%) were women. The effect size for socio-economic status was 0.47 (95% CI, 0.39–0.54) for UMAT, 0.43 (95% CI, 0.35–0.50) for UCAT total score; the effect size for remoteness was 0.54 (95% CI, 0.45–0.63) for UMAT, 0.48 (95% CI, 0.39–0.58) for UCAT total score. The impact of professional coaching on UCAT performance was not statistically significant among those accepted for interview. Conclusions: Women and people from areas outside major cities or of lower socio-economic status perform less well on the UCAT than other applicants. Reviewing the test and applicant quotas may be needed to achieve selection equity.