Background: Child maltreatment is a global phenomenon with possible serious long-term consequences. The present study aimed to determine the relationship between childhood maltreatment and opiate dependency in older age. Methods: In this study, 212 opiate dependent individuals and 216 control subjects were selected consecutively. The data collection instrument was a questionnaire which consisted of background variables, General Health Questionnaire-12 (GHQ-12), and Childhood Trauma Questionnaire (CTQ). The questionnaires were anonymously completed by both groups in a private environment after obtaining informed consents. Findings: The mean age in the addicts and non-addicts were 31.4 ± 6.7 and 30.8 ± 7.5, respectively (P = 0.367). Moreover, 84.4% of the opiate abusers and 76.9% percent of the control group were male (P = 0.051). The mean score of CTQ in the study and control groups were 47.2 ± 1.0 and 35.8 ± 0.6, respectively (P < 0.001). The frequency of all types of abuse and neglect were higher in the addicted group. While 70.3% of the study group reported at least one type of childhood maltreatment, this figure was as low as 33.8% in the control group (P < 0.001). After adjusting the two groups for differing background characteristics and the GHQ-12 score, emotional abuse (OR = 5.06), physical neglect (OR = 1.96), and sexual abuse (OR = 1.89) were proved to have significant relationships with addiction to opiates. Conclusion: The frequency of all types of childhood maltreatment in the group addicted to opiates was higher than the control group. Emotional abuse, physical neglect, and sexual abuse had significant effects after adjusting other variables. Keywords: Adolescent, Child abuse, Substance dependency.