The authors estimated the prevalence of lifetime prescription opioid-use disorder among outpatients on opioid therapy using criteria from both versions 4 and 5 of the Diagnostic and Statistical Manual of Mental Disorders (DSM). Using electronic records from a large health care system, a random sample of outpatients undergoing long-term opioid therapy for non-cancer pain was identified and 705 participants completed diagnostic interviews. The prevalence of lifetime DSM-5 opioid-use disorder among these patients was 34.9% (95% confidence interval [CI] = 30.5?39.5), similar to the prevalence of DSM-4 opioid dependence (35.5%, 95% CI = 31.1?40.2). The Kappa value between DSM-5 and DSM-4 criteria was high (Kappa = 0.873, p < 0.0001). Logistic regressions suggested DSM-5 opioid-use disorder was associated with age younger than 65 (odds ratio [OR] = 2.25, p = 0.009), history of opioid abuse (OR = 4.94, p < 0.001), higher opioid withdrawal symptoms (OR = 3.01, p = 0.008), and history of substance abuse treatment (OR = 1.62, p = 0.015), similar to DSM-4. Based on DSM-5, 21.7% of patients met criteria for moderate and 13.2% for severe opioid-use disorder, respectively. Given the changes proposed, the finding that the prevalence of and risk factors for DSM-5 opioid-use disorders were similar to DSM-4 were unexpected. Further research is advised.