He is a clinician investigator and his current research focuses on studying effective healthcare delivery in communities for uninsured vulnerable populations including undocumented residents and older adults. His areas of expertise include diabetes in older adults, the evaluation of health system and community level interventions for vulnerable populations, physician workforce diversity, social and structural determinants of health, language-based disparities in healthcare, and medical education programs. Dr. Moreno has published clinical guidelines on diabetes among older adults and studies that have increased our understanding of health disparities and the social determinants of health, and has published on other important issues addressing physician workforce diversity, family medicine, and medical education. Dr. Moreno has a continuity clinic and trains family medicine residents and UCLA medical students. He serves on the Board of Directors for the American Board of Family Medicine (ABFM) and on the NIH Clinical Aging study section (NIA-C).