PROJECT SUMMARY PrEParados is a three-year developmental R01 study that will determine how social networks impact PrEP uptake and adherence among Latino men who have sex with men (LMSM), both those who self-identify as gay, and the unstudied group of LMSM who self-identify as bisexual/straight. This study will be implemented in Miami-Dade County (Miami), the epicenter of the HIV epidemic in the US. Among racial/ethnic groups in Miami, LMSM have the highest HIV incidence. Despite PrEP being the most effective HIV prevention measure currently available, few eligible LMSM in Miami are enrolled in a PrEP program (only 6% in 2018). Our preliminary study (N=130) suggests that social network structures may be contributing to LMSM’s low PrEP use. In that study of LMSM self-identified as gay, we discovered a large proportion of sexual encounters involved bisexual/straight LMSM. Self-identified bisexual/straight LMSM are a bridge between MSM—in whom the HIV epidemic is concentrated—and the general population in Miami. Before developing interventions, we need to implement this R01, which studies a larger sample to identify network configurations and dynamics impacting HIV risk among LMSM by their sexual self-identification (gay or bisexual/straight). To inform future interventions, our study will examine how social network structural factors suppress or promote access, encouragement, uptake, and adherence to PrEP. These findings will allow better deployment of accurate information and interventions, resulting in increased PrEP initiation and adherence amongst LMSM. PrEParados will study three social networks: 1) Friendship Networks—to identify social network mechanisms that promote PrEP use among LMSM friends in Miami. 2) Sexual Networks—to distinguish homophily and dyadic characteristics and dynamics associated with PrEP communication between sexual partners. 3) Venue Networks—to determine affiliations with geographic and online venues that could increase PrEP knowledge. Our established partnerships with Latinos Salud, Miami-Dade County Health Department PrEP Clinic, and the University of Miami’s Mobile PrEP Clinic and Rapid Access Wellness Clinic will provide access to 8,000+ LMSM, including 1,500+ PrEP users and 500+ who self-identify as bisexual/straight. This R01 study will provide new information that will allow PrEP interventions to include social network components and be tailored based on LMSM’s sexual self-identification. These new interventions could then serve as models for PrEP programs targeting males from other hard to reach populations.