Background: Alcohol use disorders increase the risk for physical harm, mental or social consequences for patients and others in the communities. Studies on alcohol use disorder and associated factors among medical and surgical outpatients in Ethiopia are limited. Therefore, this study is meant to provide essential data alcohol use disorder and associated factors among medical and surgical outpatients for future interventions. Methods:An institution-based cross-sectional study was conducted using the systematic random sampling technique. Alcohol use disorder was assessed using the World Health Organization’s 10-item Alcohol Use Disorder Identification Test (AUDIT) questionnaire. Data were analyzed using the Statistical Package for Social Sciences (SPSS) version 20. Bivariate and multivariate logistic regression analyses were performed, P-values less than 0.05 were considered statistically significant in the multivariate analysisand the strength of association was measured using AOR at a 95% confidence interval.Results: The prevalence of alcohol use and use disorder were 322(68.50%) and 111(34.5%), respectively. In the multivariate analysis, male sex (AOR=3.33, 95%CI: 1.40, 7.93), history of mental illness (AOR=2.68, 95%CI: 1.12, 6.38), drinking for relaxation (AOR=1.88, 95%CI: 1.02, 3.48) and history of lifetime tobacco use (AOR=5.64, 95%CI: 1.95, 16.29) were significantly associated with the disorders. Conclusions: The prevalence of alcohol use disorders among medical and surgical outpatients was found to be high. Male sex, history of mental illness, use of alcohol for relaxation and tobacco smoking need further attention in the assessment of the disorder.