Racial and ethnic minorities remain underrepresented in clinical psychiatric research, but the reasons are not fully understood and may vary widely between minority groups. We used the Z-test of independent proportions and binary logistic regression to examine the relationship between race, ethnicity or primary language and participation in screening as well as interest in further research participation among primary care patients being screened for a depression study. Minorities were less likely than non-Hispanic Whites to complete the initial screening survey. Latinos and Blacks were more likely to agree to be contacted for research than non-Hispanic Whites. Among Latinos, primary language was associated with willingness to be contacted for research. Associations between research participation and race, ethnicity and language are complex and vary across different enrollment steps. Future research should consider stages of the research enrollment process separately to better understand barriers and identify targets for intervention.