Introduction: Recent studies have demonstrated the promise of emergency department (ED)-initiated buprenorphine/naloxone (bup/nx) for improving 30-day retention in outpatient addiction care programs for patients with opioid use disorder (OUD). We investigated whether ED-initiated bup/nx for OUD also impacts repeat ED utilization., Methods: We performed a retrospective chart review of ED patients discharged with a primary diagnosis of OUD from July 2019-December 2020. Characteristics considered included age, gender, race, insurance status, domicile status, presence of comorbid Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnosis, presenting chief complaint, and provision of a bup/nx prescription and/or naloxone kit. Primary outcomes included repeat ED visit (opioid or non-opioid related) within 30 days, 90 days, and one year. Statistical analyses included bivariate comparison and Poisson regression., Results: Of 169 participants, the majority were male (67.5%), White (82.8%), uninsured (72.2%), and in opioid withdrawal and/or requesting "detox" (75.7%). Ninety-one (53.8%) received ED-initiated bup/nx, which was independent of age, gender, race, insurance status, presence of comorbid DSM-5 diagnosis, or domicile status. Naloxone was more likely to be provided to patients who received bup/nx (97.8% vs 26.9%; P < 0.001), and bup/nx was more likely to be given to patients who presented with opioid withdrawal and/or requested "detox" (63.3% vs 36.7%; P < 0.001). Bup/nx provision was associated with decreased ED utilization for opioid-related visits at 30 days ( P = 0.04). Homelessness and lack of insurance were associated with increased ED utilization for non-opioid-related visits at 90 days ( P = 0.008 and P = 0.005, respectively), and again at one year for homelessness ( P < 0.001). When controlling for age and domicile status, the adjusted incidence rate ratio for overall ED visits was 0.56 (95% confidence interval [CI] 0.33-0.96) at 30 days, 0.43 (95% CI 0.27-0.69) at 90 days, and 0.60 (95% CI 0.39-0.92) at one year, favoring bup/nx provision., Conclusion: Initiation of bup/nx in the ED setting was associated with decreased subsequent ED utilization. Socioeconomic factors, specifically health insurance and domicile status, significantly impacted non-opioid-related ED reuse. These findings demonstrate the ED's potential as an initiation point for bup/nx and highlight the importance of considering the social risk and social need for OUD patients., Competing Interests: Conflicts of Interest: By the WestJEM article submission agreement, all authors are required to disclose all affiliations, funding sources and financial or management relationships that could be perceived as potential sources of bias. The project described was supported by Grant Number 1H79T1081609-01 from the Substance Abuse and Mental Health Services Administration (SAMHSA). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the SAMHSA.There are no conflicts of interest to declare.