Underrepresented racial minority (URM) students in science, technology, engineering, and mathematics majors encounter educational, social, and structural challenges on the path toward their degrees and careers. An undergraduate research program grounded in critical race theory was developed and implemented to address this disparity. NIH BUILD PODER focuses on developing science identities in URM students through a culturally relevant and responsive research training environment, ultimately increasing their pursuit of biomedical-related research careers. The current study examines differences in science identities and the intention to pursue a science career among a sample of undergraduate Latinx seniors (N = 102) in biomedical science majors. Three groups were examined: 1) BUILD PODER students, 2) non-BUILD PODER students who reported having a faculty mentor, and 3) non-BUILD PODER students who reported no faculty mentorship. Results revealed that BUILD PODER students reported the highest levels of science personal-identity and science social-identity upon graduation. Additionally, BUILD PODER students and non-BUILD PODER students with a mentor reported greater levels of science social-identity than those without a mentor. BUILD PODER students also reported the strongest intentions to pursue a science career after college. These results highlight the importance of identity processes in the success of Latinx college students in biomedical science majors.