Context HIV testing in jails provides an opportunity to reach individuals outside the scope of traditional screening programs. The rapid turnover of jail populations has, in the past, been a formidable barrier to offering routine access to testing. Objective To establish an opt-out, rapid HIV testing program, led by nurses on the jail staff, that would provide undiagnosed yet infected detainees opportunities to learn their status regardless of their hour of entry and duration of stay. Design Jail nurses offered rapid, opt-out HIV testing Setting Fulton County Jail (FCJ) in Georgia, United States. Participants 30,316 persons booked to FCJ. Intervention In late 2010, we performed a preliminary evaluation of HIV seroprevalence. Starting January 1, 2011, HIV testing via rapid oral mucosal swab was offered to entrants. In March 2013, fingerstick was substituted. Detainees identified as positives were assisted with linkage to care. Main outcome measures To estimate an upper limit of overall HIV prevalence among entrants, we determined seroprevalence by age and gender group. To measure program performance, we checked offer and acceptance rates for tests and rate of linkage to care among previously known and newly identified HIV+ detainees. Results The initial seroprevalence of HIV in FCJ was at least 2.18%. Between March 2013 and February 2014, 89 new confirmed positives were identified through testing. During these 12 months, 20,947 bookings were followed by an offer of HIV testing (69.10% offer rate), and 17,035 persons accepted (81.32% acceptance rate). A total of 458 previously and newly identified persons were linked to HIV care. Linkage was significantly higher among those aged 40 years and older (p<0.05). Conclusions A nurse-led, rapid HIV testing model successfully identified new HIV diagnoses. The testing program substantially decreased the number of persons who are HIV-infected but unaware of their status and promoted linkage to care.