Project Summary/Abstract: Opioid use disorder (OUD) is a pressing public health problem nationwide but is increasing rapidly in underserved communities where there is currently a shortage of services, particularly evidence-based transitional opioid programs (TOPs) which link patients in hospitals to harm reduction and treatment resources. Hospitals are ideal sites to address OUD and engage patients given the relationship between opioid use and misuse and a number of acute health conditions, including overdose and infectious disease. Evidence suggests that hospitals are highly motivated to participate in offering new interventions due to the economic and social toll of untreated OUD. Safety net hospitals, however, face considerable barriers to adopting TOPs and have been significantly less likely to offer OUD services in their communities. To engage safety-net hospitals effectively and help them implement opioid programs such as TOPs, more information is needed on implementation barriers to tailor implementation strategies that will be most effective given the local constraints faced by safety-net providers. Using a combination of the latest publicly available community benefits reports and Internal Revenue Service Schedule H data, we will catalog hospitals’ OUD services, including TOPs, and assess the relationship between the adoption of TOP and various community and hospital characteristics, including safety-net status, and examine trends in the availability of OUD services across time (Aim 1). We will then interview hospital decision makers and community partners at five diverse safety net hospitals to better understand barriers and facilitators to adopting and implementing TOPs. (Aim 2). Finally, we will convene an expert panel to identify high-yield and tailored implementation strategies to increase the availability of transitional opioid programs and other evidence-based opioid services in underserved communities (Aim 3). As an interdisciplinary team of health services researchers, we have a strong record of collaborative publication and extramural funding related to hospital-community partnerships and opioid services. The implementation strategies developed in this study will lead to a future cluster randomized controlled trial to test the effectiveness of tailoring implementation strategies to safety net settings. The long term outcome is to increase the availability of TOPs in communities where significant disparities currently exist.