Background. Pre-exposure prophylaxis (PrEP) has dramatically changed the promise of HIV prevention, particularly for gay, bisexual, and other men who have sex with men (MSM) who account for the majority of HIV infections in the U.S. Accordingly, PrEP reduces HIV acquisition by >90% with adequate adherence. However, many MSM face multiple challenges with respect to initiating, adhering to, and staying on PrEP, with particular challenges for specific MSM subgroups, specifically those experiencing multiple psychosocial problems—also known as syndemics—including depression; heavy alcohol use; polydrug use; history of trauma or abuse; current interpersonal violence; as well as being a racial/ethnic minority MSM. Preliminary Research. Life-Steps—a cognitive-behavioral therapy-based intervention—has successfully supported ART treatment and prevention adherence in various studies. With funding from an NIMH R34, we adapted the Life- Steps intervention to support PrEP adherence for MSM and conducted a 2-arm pilot RCT that showed high participant acceptability, feasibility of implementation, and promise of the “Life-Steps for PrEP” adherence intervention. Conceptual Model. The current study is to test the efficacy of a stepped-care “adaptive” Life- Steps for PrEP adherence intervention for MSM at high-risk for HIV acquisition. Stepped care is a healthcare delivery model in which the least resource intensive part of an intervention is delivered first, and only those who continue to have problems receive the higher intensity, more resource intensive parts of an intervention. The conceptual model is based on our formative work that led to the development of a theoretically-driven intervention curriculum (“Life-Steps for PrEP”), grounded in the social and contextual realities of MSM with multiple psychosocial problems at high-risk for HIV acquisition. Overview of Intervention. Our intervention begins with 2-way daily text messaging aimed at enhancing optimal PrEP adherence via reminders. Although helpful, for many MSM (~2/3 from published research), text messaging alone is not sufficient to overcome the barriers to PrEP adherence. Those not adherent (<4 pills over a 7-day period) from text reminders, will “step up” to receive Life-Steps adherence counseling. Research Plan. 250 HIV uninfected PrEP naïve MSM (at least 50% racial/ethnic minority) at risk for adherence difficulties (≥1 syndemic condition) will be recruited in two major U.S. cities with excellent access to and research experience with the population. Participants will be equally randomized to: (1) “Life-Steps for PrEP” – a stepped care, adherence intervention with integrated technology and counseling; or (2) Standard of care control group. Participants will be followed for 18-months post-randomization. The primary outcomes are enhanced maintenance of PrEP adherence (DBS TFV-DP concentrations & self-report) and retention in PrEP care; we will also examine improvements in PrEP adherence skills and con...