Abstract Advances in HIV prevention and treatment interventions, together with unprecedented investments to bring these interventions to scale, presents an opportunity to prevent new infections, avert HIV-related morbidity and mortality, and dramatically alter the HIV/AIDS epidemic. However, the full potential of scientific advances in HIV treatment and prevention has yet to be realized, and efficacious interventions have not been adequately scaled into effective programs. Implementation science can improve the uptake and effectiveness of these programs, and impact health at the population level. Given the imperative to translate evidence-based interventions into widely implemented programs, implementation science is a scientific priority for the NIH, domestic and global public health agencies, and UW/Fred Hutch CFAR members. The UW/Fred Hutch CFAR is ideally situated to continue to link implementation science research with public health programs both within the U.S., and globally. Our CFAR faculty is at the forefront in defining multidisciplinary, implementation science research methods, and has developed novel training curricula in public health and implementation science. Furthermore, CFAR-affiliated investigators lead diverse programs to implement and scale-up HIV prevention and treatment interventions that have developed strong, collaborative relationships with health departments throughout the U.S. and internationally. In the last competitive renewal, we transitioned the Implementation Science Scientific Working Group into a Core that developed implementation science expertise within the CFAR community, fostered new interdisciplinary implementation science research, and linked research and public health activities to promote implementation science in real-world public health settings. For the next renewal period we propose to continue high value training opportunities for junior researchers, lead to new and innovative research, and ultimately improve the speed, efficiency, and quality of efforts to translate scientific evidence on HIV prevention and care into effective, large scale health programs. The IS Core’s specific aims are to: 1) Build capacity in HIV- focused implementation science research through short courses and seminars; 2) Increase externally funded domestic and international HIV-focused implementation science research; and 3) Develop a cadre of early-stage investigators in implementation science HIV/AIDS research through a Junior Investigator Mentorship Group. To advance these aims the IS Core will support trainings and seminars to build investigators’ skills related to implementation science and draw new researchers into the field; provide consulting and analytic expertise to CFAR-affiliated researchers on grant applications and in support of ongoing projects in areas related to implementation science; create linkages between CFAR investigators and international and domestic health departments to identify and cultivate co...