PROJECT SUMMARY The University of Arizona (UArizona) MARC program provides research experiences, formal and informal mentoring, financial support and professional development training to upper-division underrepresented students who have an interest in and potential to pursue biomedical research careers. The program seeks to increase the number of such students entering PhD programs. The overarching objectives are to support 14 MARC trainees per year in two cohorts beginning June 2023 and for 85% of the trainees to complete the program, graduate from UArizona and matriculate in PhD or combined-PhD/MD programs by Fall 2029. The trainees will be underrepresented honors students from 14 biomedically-relevant majors distributed in 12 departments across four colleges at UArizona. Outstanding, well-funded UArizona MARC training faculty will provide research guidance and intensive mentoring, drawing upon their significant experience with undergraduates and their commitment to training underrepresented students. Trainees will also be formally mentored by the Program Director and Associate Director. Through the Minority Biomedical Research Colloquium series, trainees will meet prominent scientists from other institutions, as well as former UArizona MARC trainees, who are currently in or recently graduated from PhD programs. Trainees will attend workshops on responsible conduct of research, research safety and minority health disparities; take part in a scientific writing course; attend national scientific meetings; participate in intramural and extramural research; present posters at campus and national conferences; give oral presentations in the Research Colloquium series and other forums and attend workshops on the graduate application process. Each trainee will be provided individualized support on graduate school applications and will be coached through the interview and selection process. The UArizona MARC program will also encourage lower-division underrepresented students to perform well academically so as to secure MARC traineeships and thus prepare for careers in biomedical research. The MARC program has been iteratively designed based on feedback from former and current trainees, the program evaluator and the internal Advisory Committee. The success of this responsive program design is evident in metrics from the past funding cycle in that the percentage of underrepresented trainees entering biomedical doctoral research programs improved from 70% for the first cohort (2017–2018) to 90% for the fourth cohort (2020–2021). The MARC Program Director, Associate Director and Assistant Director have and will continue to provide persistent, seamless and inclusive support for trainees. We will continue to provide effective activities and inclusive support to enhance the transition of our trainees into biomedical research doctoral programs.