Background:Alcohol use disorders (AUDs) are common in men who have sex with men (MSM) and transgender women (TGW) in Peru and undermine antiretroviral therapy (ART) adherence. Oral naltrexone (NTX) is an evidence-based treatment for AUD that has not been assessed in cotreating AUD in MSM/TGW with HIV.Setting and Design:A multi-site, randomized, double-blind, placebo-controlled trial among MSM/TGW with AUD and newly diagnosed with HIV in Lima, Peru.Methods:Newly diagnosed MSM/TGW with HIV and AUD were prescribed a single-treatment regimen of EFV/TDF/FTC from 2014 to 2015 and randomized 2:1 to oral NTX (N = 103) or placebo (N = 53) for 24 weeks. The primary and secondary outcomes were proportion achieving viral suppression (VS: HIV-1 RNA < 400 copies/mL) or maximal viral suppression (MVS: HIV-1 RNA < 40 copies/mL) at 24 weeks.Results:There were no significant differences between the arms in VS (81.6% NTX arm vs 75.5% placebo arm; P = 0.37) or MVS (61.2% NTX arm vs 66.0% placebo arm; P = 0.48). Adherence to study medication was low (mean = 34.6%) overall with only 21.4% of participants meeting recommended adherence levels (≥80% daily doses/month). Participants allocated to NTX had significantly lower adherence compared with placebo for both the first and second 12-week study periods, respectively (44.0% vs 35.2%, P = 0.04; 31.4% vs 35.2%, P = 0.03).Conclusions:Findings are inconclusive regarding the use of NTX for treatment of AUD in MSM/TGW newly diagnosed with HIV. VS and MVS levels were high irrespective of allocation. Adherence to study medication was low, requiring further exploration of strategies to optimize adherence to NTX as AUD treatment.