PROJECT SUMMARY/ABSTRACT The laboratory mouse is the premier animal model for studying human disease. Yet creation of mouse models is outpacing the professional development and training of pathologists prepared to interpret the tissue abnormalities that arise in mice experimentally manipulated, genetically engineered, within long-term aging studies, or that develop spontaneous diseases. We propose to continue the annual Workshop on the Pathology of Mouse Models for Human Disease to provide intense, interactive, training sessions aimed at the next generation of veterinary and physician pathologists. A productive core group of organizing pathologists will gather a rotating group of pathology specialists and research scientists, with 20% new presenters each year, to deliver annual, 5 day long workshops each October from 2019-2021. The Jackson Laboratory (JAX) in Bar Harbor, Maine will host the workshops; JAX continues to be a unique institution with a strong focus on the genetics, biology, and pathology of laboratory mice. Workshop topics cover a range of diseases, not just neoplastic, from those associated with aging to embryonic developmental abnormalities. Specific organ systems will include, skin, bones, eyes, intestinal tract, pulmonary system, etc. Training will include presentations on emerging technologies for creating genetically engineered mice, database resources facilitating analyses and pathological cases studies contributed by participants and organizers. Participation will remain ~25 to maximize interactions between the faculty and attendees, thereby encouraging networking and collaboration. Our long-term objective is to develop a highly skilled cadre of comparative pathologists capable of interpreting mouse lesions and applying this knowledge to research and training programs at their respective institutions throughout the United States and beyond. We will also carry out a plan to have appropriate representation of traditionally underrepresented individuals as workshop participants, using well- established mechanisms at JAX and offering partial scholarships. Our innovative and comprehensive workshop will offer a critical, unique training experience that is best delivered at JAX.