Objective: The current study aimed to assess the factor structure, validity, and reliability of the Persian version of Severity of Dependence Scale in alcohol and substance dependent individuals in Iran. In addition, the SDS scores were assessed in terms of a number of demographic factors. Method: SDS was translated to Persian and was subsequently translated back into English. Furthermore, it was compared with the original scale. Essential revisions were made into the scale after its preliminary administration to 20 participants. Thereafter, 281 alcohol/ substance dependent individuals from prison, dormitory, and various rehabilitation camps were chosen and completed the questionnaire. Questionnaires of demographic information, Severity of Dependence Scale (SDS), Leeds Dependence Questionnaire (LDQ), Drug Use Disorders Identification Test (DUDIT), and brain-behavioral systems scale were used in order to obtain data. Data were analyzed via LISREL8/8 software and appropriate statistical tests. Results: The results supported the one-factor structure of SDS. The scale reliability coefficients were obtained equal to 0.64 and 0.58 through Cronbach’s Alpha and Guttman, respectively. Convergent validity of the scale was obtained equal to 0.46 and 0.37 by correlating SDS with DUDIT and LDQ, respectively. The results also reported the existence of a significant difference in the mean of SDS scores when the history of consumption in family, the place of habitation, and the type of drug were at play. Conclusion: SDS maintains acceptable reliability and validity. Hence, it appears plausible to use this questionnaire for the assessment of alcohol and substance dependency among dependent individuals in Iran. It is required to pay attention to the demographic factors affecting dependence severity planning on prevention and treatment of this disorder.