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HIV and hepatitis C virus (HCV) testing for all people in jail is recommended by the CDC. In the community, there are barriers to HIV and HCV testing for minoritized people. We examined the relationship between race and infectious diseases (HIV, HCV, syphilis) testing in one Massachusetts jail, Middlesex House of Corrections (MHOC). This is a retrospective analysis of people incarcerated at MHOC who opted-in to infectious diseases testing between 2016–2020. Variables of interest were race/ethnicity, self-identified history of psychiatric illness, and ever having experienced restrictive housing. Twenty-three percent (1,688/8,467) of people who were incarcerated requested testing at intake. Of those, only 38% received testing. Black non-Hispanic (25%) and Hispanic people (30%) were more likely to request testing than white people (19%). Hispanic people (16%, AOR 1.69(1.24–2.29) were more likely to receive a test result compared to their white non-Hispanic (8%, AOR 1.54(1.10–2.15)) counterparts. Black non-Hispanic and Hispanic people were more likely to opt-in to and complete infectious disease testing than white people. These findings could be related to racial disparities in access to care in the community. Additionally, just over one-third of people who requested testing received it, underscoring that there is room for improvement in ensuring testing is completed. We hope our collaborative efforts with jail professionals can encourage other cross-disciplinary investigations.