This application requests support to continue the Host-Microbe Interactions (HMI) Predoctoral Training Program which is an interdisciplinary training program that seeks to provide research and curricular-based training to a pool of talented and highly motivated students who seek training in microbial pathogenesis and beneficial host-microbe interactions. The HMI program consists of 18 Training Faculty who have an average of $736,699 direct costs per year, and annual direct costs for research total to $13.3 million. Trainers currently have 72 trainees in their labs. Areas of strength among our Trainers include molecular genetics of bacterial, fungal, and viral pathogenesis, and prion biology, study of the microbiome, interaction with immune and epithelial cells, and ecological modeling. These areas are pursued using the full range of modern genetic, molecular, biochemical, immunologic, and computational techniques. Trainees are supported by one of three excellent multidisciplinary graduate programs, the Microbiology and Molecular Pathogenesis program (M2P2), and the Guarini School of Graduate and Advanced Studies. We have both hired new faculty whose research is directly aligned with the program goals, indicating the institution’s commitment to research in microbiology and recruited to our program Dartmouth faculty whose research in host-microbe interactions has expanded. Most importantly, our past Trainees have been extremely successful. Of the 33 HMI Training Program Trainees who have left Dartmouth in the past 15 years, 32 are in PhD-level careers in science and one is a high school science teacher and thus is still leveraging their training. HMI Trainees from the past ten years have published 83 papers. In the past four years since the last renewal, we have made several positive changes to the program including 1) mentor training from the Center for the Improvement of the Mentored Experiences in Research (CIMER) with 94% of our Trainers having already completed training, 2) increased the involvement of early career or new-to-Dartmouth faculty in program subcommittees, 3) enhanced support for preparation of F31 applications, and 4) focus of a Trainee curriculum that is broadly useful across sub-disciplines within the area of host-microbe interactions. To continue our positive impact on the biomedical workforce, we request to continue supporting five trainees per year.