The UC San Diego MADURA Mentorship Program, funded by an R25 National Institute on Aging grant, has goals to improve diversity in Aging and Alzheimer’s Disease (ADRD) research and clinical practice. MADURA strives to improve retention and academic success of its URM trainees, and to increase graduate/medical school applications and/or entry into Aging/ADRD careers. Mentees receive paid research experience, skills training, peer support, seminars, and additional professional development opportunities. Given local demographics and Co-Investigator expertise, MADURA recruits primarily Hispanic/Latinx (H/L) students, and other URM students. Non-exclusive racial identifications of 32 Year 1 mentees were: 69% H/L, 9% Black/African American, 22% Asian and 31% other race. 72% met NIH criteria for Disadvantaged Backgrounds. As of June 2021, 100% of students completed surveys assessing Racial Microaggressions and Imposter Syndrome experiences, and Professional Self-efficacy. This poster will define the concepts, discuss relevance for URM student success and retention, and present student data on each topic. As examples, 56% of trainees experienced overt discrimination and 72% reported having experienced microaggressions at least occasionally, as undergraduates. As related to Imposter Syndrome, 62% secretly worried that others would find out that they are not as bright and capable as others think. Half attributed accomplishments to being a “fluke,” or due to reasons other than true merit. Still, in terms of Professional Self-efficacy, 62% of mentees thought it moderately or very likely that they would succeed as an Aging/ADRD researcher. The authors will make specific suggestions for optimized URM training and mentorship program content, and provide resources.