The Nonhuman Primate Transplantation Tolerance Cooperative Study Group (NHPCSG) was established to advance transplantation research through use of nonhuman primate (NHP) models. Because NHPs more closely approximate human physiology, immunology, and genetics compared to other available models, they remain the most rigorous and ethically sound model for testing novel therapeutics and transplantation tolerance approaches prior to clinical translation. High-quality specific pathogen free (SPF) monkeys are required for transplantation studies because the use of immunosuppressive therapies during the period of experimental tolerance induction increases risk of serious complications due to certain infectious diseases. This Association for Assessment and Accreditation of Laboratory Animal Care International (AAALAC) accredited contractor is tasked with providing all aspects of the NIAID colonies’ SPF maintenance, breeding, and medical care, as well as routine genetic diversity assessment and planning; pedigree and major histocompatibility complex (MHC) testing; and timely provision of animals to NIAID-funded awardees, with priority given to NHPCSG investigators.