In the US, 20.9% of the Latino men who have sex with men and transwomen (LMSMT) are unaware of their HIV status. Undiagnosed HIV positive persons cannot receive treatments that increase quality of life and reduce infectivity. To benefit from early diagnosis, the CDC suggests that groups at higher HIV risk get tested regularly. Despite the many strategies to encourage HIV testing, there are few that promote regular HIV testing among LMSMT, and none has considered the realities of the LMSMT in the US Heartland. We will evaluate the efficacy of LUPA, an intervention to promote regular HIV testing and prevention (risk reduction and PrEP awareness and referrals) among friendship networks of LMSMT in midsized Midwestern cities. These cities have large numbers of LMSMT among whom HIV prevalence rates are 2 to 9 times higher than among Whites. LMSMT in these smaller and more conservative urban areas experience more limited sexual options and higher social costs of using HIV preventive care, increasing the likelihood of HIV exposure and hampering high-impact HIV prevention. LUPA uses the relationships that permeate networks of LMSMT by training well- positioned members to encourage a collective response to the epidemic and to disseminate HIV testing and prevention messages and resources within the network. A network approach reflects the dynamics of the HIV epidemic and is consistent with Latinos' cultural orientation to the group. We conducted a R34 pilot randomized controlled trial to evaluate the acceptability, feasibility and promise of LUPA with LMSMT in Milwaukee (N = 107, Med age 26). We recruited 6 networks of LMSMT, tested them for HIV and suggested that they get tested regularly. We identified key members in 3 randomly selected networks and invited them to a 6-week training to deliver messages to others in the network. Messages aimed to increase motivation and skills for risk reduction, develop reminders and action plans for regular testing, and disseminate latest generation HIV-prevention tools. Twelve of 15 LMSMT attended the training sessions, reaching 46 LMSMT friends with messages supervised by LUPA facilitators. At 12-month follow up, compared with the networks that received only HIV testing, LUPA networks reported more conversations on intervention topics and differences suggestive of positive effects on biannual testing, sexual risk, and PrEP intentions. This full-scale trial aims to: (1) Evaluate, among LMSMT in 3 Midwestern cities, the efficacy of LUPA to increase HIV testing at 6-month intervals, as well as safer sexual behavior and PrEP awareness and referrals; and (2) Identify the structural (access to services and latest generation HIV prevention), and the motivational and behavioral mediators of LUPA effects. We will (a) recruit 36 friendship networks of LMSMT in Milwaukee, Cleveland, and Indianapolis (N ≈ 432); (b) test them for HIV and recommend that they test regularly; (c) invite key members of 18 randomly selected networks to...