Abstract The aims of this project are to provide healthy, behaviorally normal, MHC-characterized, SPF pig-tailed macaques for NIH-funded HIV/AIDS related research. We will expand the size of the current SPF breeding colony to increase the numbers of females for breeding and juvenile males and females available for sale to NIH-funded HIV/AIDS investigators both within Johns Hopkins University and at other research institutions. Complete pedigrees and health data are maintained and provided to investigators when animals are being selected for sale. Viral screening includes regular serologic and PCR testing for 4 viral agents: Cercopithecine herpesvirus 1 (B virus), Simian Immunodeficiency Virus (SIV), Simian Retrovirus (SRV), and Simian T- lymphotrophic Virus (STLV). For the past decade the colony has consistently and repeatedly tested negative for these agents. Major histocompatibility (MHC) profiles are performed on all juveniles during the first year of life and are provided to investigators when animals are being selected for purchase. Over the last five years, the colony has produced an average of 51 offspring each year, resulting in an average of 32 animals sold. We estimate that selling 42 animals per year would allow the colony to achieve self-sufficiency, a goal we project we will reach by the end of 2028.