The sophisticated nature of mouse research, including phenotypic characterization, can be significantly confounded by the effects of intercurrent infectious disease, environmental factors, and incomplete stabilization of background genetics. Furthermore, many genomically altered mice require assisted breeding approaches for maintenance of the strain. The MBP can assist investigators with these significant issues by rederiving mice by embryo transfer, cryopreservation of germplasm to protect against catastrophic loss, assisted breeding (including in vitro fertilization and ovarian transplantation), genetic management, backcrossing (including speed congenics), genotyping, barrier maintenance, specialized nutritional and husbandry support, infectious disease surveillance, veterinary care, and diagnostic support. Embryo, sperm, oocyte, and tissue freezing capabilities are available. The MBP is enagaged in advancing these various technologies to make them more efficient and cost-effective. The MBP maintains mice in facilities that are fully accredited by the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC) International, and benefits from the substantial professional expertise within the world's leading School of Veterinary Medicine. Exceptionally skilled husbandry and breeding colony management is provided by MBP staff and the Center for Laboratory Animal Science (CLAS).