INTRODUCTION: The opioid epidemic continues to grow, placing a significant strain on Emergency Departments (EDs), resulting in patients presenting daily with opioid-related concerns including intoxication, withdrawal, infections, injury, and death. Consequently, in recent years many EDs, including our own, have utilized Emergency Department Observation Units (EDOU) to not only manage withdrawal and overdose, but also initiate long-term treatment. This study aims to evaluate the outcomes of patients with opioid use disorder (OUD) who were managed in our EDOU. METHODS: This was a retrospective study of patients placed in an EDOU who had the primary diagnosis of OUD in a single large, urban, tertiary academic hospital from May to November 2021. Demographic data and factors related to the ED visit and EDOU actions (e.g., use of peer navigator services, buprenorphine dose and prescription, distribution of naloxone discharge kits, and addiction clinic referral) were analyzed. The primary outcome variables were complications after buprenorphine use (e.g., precipitated withdrawal), the number of repeat ED visits or subsequent hospitalizations within 30 days for both all causes and opioid-related causes, and fatalities within 30 days of EDOU discharge. RESULTS: Twenty-nine patients were identified for chart review. Of these, 59 % were male. The median age was 55 years. Additionally, 93 % of the patients were insured, 66 % had housing, 72 % possessed a phone, and none were employed. During EDOU stays, 48 % [95 % CI 0.2989, 0.6711] of patients received buprenorphine with a total mean dose of 19 mg (SD, 10.6 mg). Upon discharge from the EDOU, 48 % [95 % CI 0.2989, 0.6711] were prescribed buprenorphine, 14 % [95 % CI 0.0451, 0.3257] received a naloxone discharge kit, and 45 % [95 % CI 0.2696, 0.6402] received an addiction clinic appointment. No patients had precipitated withdrawal, serious adverse events, or upgrades to inpatient care. Within 30-days of EDOU discharge, 38 % [95 % CI 0.213, 0.5764] of patients had a subsequent ED visit for any cause, and 6.9 % [95 % CI 1.2, 2.2] had a subsequent hospitalization for any cause. There were no fatalities within 30 days of EDOU discharge. CONCLUSION: The EDOU can serve as a promising location to provide quality care for patients presenting to the ED with OUD, with minimal adverse effects. There were few subsequent hospitalizations following discharge from the EDOU. Further non-observational studies regarding OUD management in an EDOU setting should be performed to optimize care and improve clinical outcomes and healthcare utilization.