Project Summary/Abstract Opioid agonist therapies (i.e. buprenorphine and methadone) are first-line treatments for opioid use disorder (OUD) and overdose prevention. Sequalae of alcohol use disorder (AUD) can interfere with opioid agonist therapy retention, worsen OUD symptoms, and increase risk of overdose. Contingency management (CM) is an evidence-based approach for promoting opioid agonist retention and alcohol abstinence that could address both behaviors simultaneously to improve outcomes for co-occurring opioid and alcohol use disorder (OUD- AUD). This study will pilot an innovative and highly scalable digital CM treatment, delivered via mobile device, among Medicaid beneficiaries with OUD-AUD and conduct implementation strategy development for a future effectiveness-implementation hybrid trial. The study includes three aims. Aim 1 will identify optimal settings and approaches to engage Medicaid beneficiaries with OUD-AUD in digital CM through analysis of Medicaid claims data. Aim 2 will convene an Advisory Board to develop a roadmap for implementation, sustainability, and health equity for digital CM in real-world care, and Aim 3 will include a mixed methods randomized pilot trial to test feasibility and acceptability of digital CM for OUD-AUD. We will compare opioid agonist retention and alcohol abstinence during the intervention period and follow-ups among those randomized to digital CM vs. an attention- and incentive-matched comparison condition. Exit interviews with participants and index sites will elucidate patient and provider perceptions of factors influencing digital CM adoption to inform the future effectiveness-implementation hybrid trial. Together, these aims will ensure inclusion of a diverse, representative sample from appropriate clinical locations guided by Medicaid claims data, perspectives from Medicaid beneficiaries with lived experience of OUD-AUD, and our Advisory Board—hastening research-to- practice translation. Digital CM optimized for use with Medicaid beneficiaries with OUD-AUD could address a major public health problem among a diverse and underserved population. This study’s emphasis on implementation, sustainability, and health equity aligns with national priorities to address real-world complexities of addressing co-occurring OUD-AUD, with high likelihood of real-world impact.