The Transgenic Resources Program (TRP) is a core facility dedicated to the production and maintenance of transgenic and gene-targeted mice for a wide variety of scientific disciplines. The TRP, located in the Magnuson Health Sciences Building in Seattle, Washington, has been in operation since 1995. Full scale technologies are available including random integration overexpression, ES cell technology, gene targeted knockouts, knockins, point mutations, inducible and temporal expression systems, as well as embryo cryopreservation and rederivation. Our services are available to all University of Washington investigators and outside institutions.