Implementation Science Core – Summary Many interventions have been developed and tested for elimination of mother-to-child transmission but the translation and implementation of these interventions into real-world settings has remained limited. Implementation science provides the necessary tools to ensure that interventions are implemented well and their impact in real-world settings is realized. The goal of the implementation science core is to provide scientific support to each of the PRI3SM implementation science research projects to ensure the latest principles and approaches in implementation science are applied appropriately to maximize the impact of the research projects through the following aims: Aim 1. To provide support and resources to enable investigators at UNC Project Malawi to effectively implement evidence-based EMTCT interventions. The implementation science core will provide assistance with selection and application of implementation science study designs to guide protocol development; identification, selection, and adaptation of implementation strategies to facilitate implementation of PRI3SM projects; selection of appropriate implementation outcomes and assistance in the development and validation of data collection tools for measuring implementation outcomes of the PRI3SM projects; implementation, monitoring and evaluation of evidence-based PRI3SM interventions in real-world settings; identification of key barriers and facilitators to implementing PRI3SM interventions; organizational readiness assessments for implementation of the PRI3SM projects and supporting qualitative measurement of implementation science outcomes and construct such as acceptability, feasibility, barriers and facilitators and organizational readiness. Aim 2: To provide trainees and junior investigators from existing local IS training programs with opportunities for real-world application of implementation science concepts. The Implementation Science Core will provide internship and fellowship placements and mentored experiential training in implementation science for junior investigators such as master’s and PhD students and graduates from existing implementation science training programs. The Implementation Science Core will leverage the capacity building program for PRI3SM to fully establish an Implementation Science Unit at UNC Project Malawi for ongoing support with implementation science training and resources. The ongoing support will include formal meetings and a seminar series with trainees to provide a platform for exchange of skills and experiences, presentations on projects and relevant implementation science topics, and review of manuscripts.