['Benzodiazepine (BZD) misuse in opioid-maintained patients is widespread and has been related to poorer treatment success. Associated factors, in particular, traumatic childhood experiences, have not been investigated extensively.', 'Cross-sectional survey including the childhood trauma questionnaire (CTQ) and clinical data among 193 patients prescribed oral opioids or injectable diacetylmorphine for opioid dependence.', 'BZD use was prevalent (61%) and the burden of childhood traumatic experiences was high with 67% reporting at least one trauma subscore of moderate-to-severe level. In univariate analysis, CTQ-subcategories "emotional abuse" (p<0.05), "emotional neglect" (p<0.01) and "physical neglect" (p<0.001) were significantly associated with prolonged BZD use. In multivariate analysis, prolonged BZD use was associated with categorized overall CTQ-scores (OR 1.5), HCV-seropositivity (OR 4.0), psychiatric family history (OR 2.3), and opioid dose (mg methadone equivalents, OR 1.010).'] Is prolonged use of benzodiazepines associated with childhood trauma in opioid-maintained patients?