Importance:Diagnosis of human immunodeficiency virus (HIV) infection, linkage and retention in care, and adherence to antiretroviral therapy are steps in the care continuum enabling consistent viral suppression for people living with HIV, extending longevity and preventing further transmission. While incarcerated, people living with HIV receive antiretroviral therapy and achieve viral suppression more consistently than after they are released. No interventions have shown sustained viral suppression after jail release. Objective:To test the effect on viral suppression in released inmates of the manualized LINK LA (Linking Inmates to Care in Los Angeles) peer navigation intervention compared with standard transitional case management controls. Design, Setting, and Participants:Randomized clinical trial conducted from December 2012 through October 2016 with people living with HIV being released from Los Angeles (LA) County Jail. All participants were (1) 18 years or older; (2) either men or transgender women diagnosed with HIV; (3) English speaking; (4) selected for the transitional case management program prior to enrollment; (5) residing in LA County; and (6) eligible for antiretroviral therapy. Main Outcomes and Measures:Change in HIV viral suppression (<75 copies/mL) over a 12-month period. Interventions:During the 12-session, 24-week LINK LA Peer Navigation intervention, trained peer navigators counseled participants on goal setting and problem solving around barriers to HIV care and adherence, starting while the participants were still in jail. After their release, they continued counseling while they accompanied participants to 2 HIV care visits, then facilitated communication with clinicians during visits. Results:Of 356 participants randomized, 151 (42%) were black; 110 (31%) were Latino; 303 (85%) were men; 53 (15%) were transgender women; and the mean (SD) age was 39.5 (10.4) years. At 12 months, viral suppression was achieved by 62 (49.6%) of 125 participants in the peer navigation (intervention) arm compared with 45 (36.0%) of 125 in the transitional case management (control) arm, for an unadjusted treatment difference of 13.6% (95% CI, 1.34%-25.9%; P = .03). In the repeated measures, random effects, logistic model the adjusted probability of viral suppression declined from 52% at baseline to 30% among controls, while those in the peer navigation arm maintained viral suppression at 49% from baseline to 12 months, for a difference-in-difference of 22% (95% CI, 0.03-0.41; P = .02). Conclusions and Relevance:The LINK LA peer navigation intervention was successful at preventing declines in viral suppression, typically seen after release from incarceration, compared with standard transitional case management. Future research should examine ways to strengthen the intervention to increase viral suppression above baseline levels. Trial Registration:clinicaltrials.gov Identifier: NCT01406626.