Abstract Among all age cohorts in the United States, emerging adults have the highest prevalence of alcohol use and about one-third (32%) engage in binge drinking (4 to 5 drinks in two hours females/males). While Latinx emerging adults report lower rates of heavy alcohol use compared to their non-Latinx White counterparts, Latinx who do drink are at greater risk for transitioning to substance use disorders and experience more severe negative consequences. Relative to other racial/ethnic groups, Latinx emerging adults who engage in problematic drinking are (a) less likely to seek treatment, and (b) have less access to innovative and accessible health promoting resources, exacerbating health inequities. Increasing evidence supports the utility of mindfulness-based interventions (MBIs) for reducing problematic alcohol use and promoting a sustainable healthy lifestyle. However, research on MBIs to address alcohol use problems is limited by (1) minimal racial/ethnic minority representation and (2) low rates of program adherence and retention. The long-term goal of this research is to decrease alcohol misuse among Latinx emerging adult drinkers through a culturally and developmentally adapted mindfulness-based intervention program targeting self-regulatory processes. The primary aims of the study are twofold. Primary Aim 1 - Use Community-Based Participatory Research (CBPR) methods guided by the five stages of cultural adaptations of behavioral health interventions to ensure a culturally and developmentally appropriate adaptation of mindfulness-based stress reduction (MBSR-L) for Latinx emerging adults (18-25 years-old) who report 2 or more binge drinking episodes in the prior 30 days. These formative stages of the research will include an expert advisory panel review, key informant interviews (n=15), focus groups (n=30) and a pilot trial (n=10; 8-weeks with weekly hour-long adapted MBSR sessions). Formative data will be analyzed to obtain information on structure, duration, acceptability, and cultural appropriateness and further refinement of intervention protocols. Primary Aim 2 – Conduct a Cultural Adaptation Trial to evaluate the acceptability and feasibility of the adapted MBSR-L intervention among a community sample (n=120) of Latinx underage emerging adults who report 2 or more binge drinking episodes in the prior 30 days. Participants will be randomly assigned to an MBSR-L condition (8 weekly 1-hour adapted MBSR-L sessions) or an assessment-only control condition. Secondary Aim 2.1 - Examine initial evidence of the efficacy of the MBSR-L intervention. We hypothesize that, relative to the participants in the control condition, participants in the MBSR-L condition will report: (a) greater reductions in frequency of binge drinking episodes and number of drinks per drinking occasion, and (b) greater impacts on putative mechanisms of change (e.g., reduced stress, greater self-regulation, and enhanced well-being). The proposed study has significant ...