Background: Opioid use disorder (OUD) affects a significant number of VA patients, and has serious consequences, including overdose and death. While medication is recognized as the most effective treatment for OUD, it remains under-utilized within VA. This is particularly true for rural patients, who are 37% less likely to receive a medication for OUD than Veterans residing in urban areas. Addressing the rural disparity in access to medication has become increasingly important as rural areas have been disproportionately impacted by the consequences of the opioid crisis, including opioid-related mortality. Significance/Impact: Enhancing access to medication for OUD for all Veterans is a major priority within VA. The research proposed will address a substantial disparity in health care access for rural Veterans, and has the potential to positively impact thousands of rural Veterans with OUD who currently lack access to evidence- based OUD treatment. Innovation: The proposed research leverages the knowledge and experience of rural facilities that have been successful in integrating buprenorphine into primary care to inform the design of an implementation strategy to support rural, primary care buprenorphine treatment. Specific Aims: Aim 1: Characterize a) VA facilities’ rates of primary care buprenorphine prescribing over time and b) differences in primary care-based buprenorphine prescribing for rural versus urban Veterans. Aim 2) Among rural facilities with improved primary care based buprenorphine prescribing, qualitatively explore implementation strategies utilized, facilitators to success, and methods to overcome implementation barriers. Aim 3) Develop and pilot test an implementation strategy to facilitate the initiation and scale-up of buprenorphine prescribing in rural CBOCs within one VA facility. Methodology: This study utilizes a mixed methods sequential explanatory design, in which findings from each Aim inform the design and conduct of subsequent Aims, which themselves contextualize and elaborate upon initial findings. Aim 1 is a retrospective cohort study utilizing national VA data. Aim 2 utilizes qualitative interviews with a sample of clinical administrators and direct care providers embedded within rural facilities that have improved their rate of primary care-based buprenorphine prescribing over time. Aim 3 is a pilot trial of the implementation strategy that will be evaluated via formative evaluation methods. Next Steps/Implementation: The Aim 3 pilot will inform IIR #2 in year 5 of the CDA, which will be a multi- center trial of the implementation strategy within rural CBOCs of VISN 20, comprising Alaska, Washington, Oregon, and Idaho—states with a considerable number of rural primary care locations.