Kleinman, MaryBackground/Objectives: Successful engagement with and retention in medication treatment for opioid use disorder (MOUD) is an important focus in the fight against the opioid crisis. Gaps in opioid use disorder (OUD) care point to a need for improved understanding of factors that affect MOUD outcomes and how barriers may act as syndemic factors, compounding one another’s effects. This study used qualitative methods to solicit feedback about barriers to retention and successful treatment outcomes in methadone maintenance treatment (MMT) and used these findings to build a conceptual framework of interaction. Methods: This study was conducted at a community-based drug treatment center that serves a low-income population, the majority of whom identify as Black or African American. We recruited patients and staff as well as peer recovery coaches who work in OUD recovery across Baltimore City. Semi-structured interviews and focus groups asked about factors that influence MMT treatment outcomes and how barriers co-occur and interact. We used thematic analysis to examine themes pertaining to our research questions and two independent coders coded each transcript based on identified themes. Results: Patient participants (n=20) had a mean age of 48.4 (SD=10.0), 70% male, and 60% Black or African American. Mean reported age of first drug use was 17.7 (SD=5.1). Staff and peer recovery coach (PRC) participants (n=12) had a mean age of 49.2 (SD= 0.7), were 42% male, 75% Black or African American, with an average of 9.6 years working in substance use (SU) treatment. Barriers described by participants fit into several broad themes: individual/self, social, institutional or structural, community or environmental, and stigma. Participants described co-occurrence of these barriers as fueling one another and having a disastrous effect on treatment outcomes. Conclusions: Understanding barriers to successful MOUD (specifically MMT) outcomes experienced by this vulnerable population and considering the synergistic effect of these barriers may assist with identification and promotion of the types of interventions needed to effectively and efficiently mitigate their impact. The conceptual model developed in the analysis of qualitative results for this study can inform future research, including quantitative analysis to build further support for the syndemic relationships presented in the model.syndemicsmethadoneopioid use disordertreatment outcomessocial determinants of healthThesis