en Health Health Original Research Original Research <p dir="ltr" style="text-align: justify"><strong>Background: </strong>The horror of HIV/AIDS as a non-curable, grueling disease is a destructive issue for every country. Drug use, shared needles and unsafe sex are closely linked to the transmission of HIV/AIDS. Modification or changing unhealthy behavior through educational programs can lead to HIV prevention. The aim of this study was to evaluate the efficiency of theory-based education intervention on HIV prevention transmission in drug addicts.</p> <p dir="ltr" style="text-align: justify"><strong>Methods</strong>: In this quasi-experimental study, 69 male drug injecting users were entered in to the theory-based educational intervention. Data were collected using a questionnaire, before and 3 months after four sessions (group discussions, lecture, film displaying and role play) of educational intervention.</p> <p dir="ltr" style="text-align: justify"><strong>Results</strong>: The findings signified that the mean scores of constructs (self-efficacy, susceptibility, severity and benefit) significantly increased after the educational intervention, and the perceived barriers decreased (p< 0.001). Also, the history of HIV testing was reported to be 9% before the intervention, while the rate increased to 88% after the intervention.</p> <p dir="ltr" style="text-align: justify"><strong>Conclusion</strong>: The present research offers a primary founding for planning and implementing a theory based educational program to prevent HIV/AIDS transmission in drug injecting addicts. This research revealed that health educational intervention improved preventive behaviors and the knowledge of HIV/AIDS participants.</p> Drug abusers, Addiction, Substance, Preventive Health Education. 15 25 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-943&slc_lang=en&sid=1 Mahmood Karimy karimymahmood@yahoo.com 200319475328460020263 200319475328460020263 No Saveh University of Medical Sciences, Saveh, Iran. Ahmad Reza Abedi Abedi.a@ArakMU.ac.ir 200319475328460020264 200319475328460020264 Yes School of Nursing & Midwifery, Arak University of Medical Sciences, Arak, Iran. Hamid Abredari hamid_abredari@yahoo.com 200319475328460020265 200319475328460020265 No Saveh University of Medical Sciences, &Kaveh Industrial Estate Company Saveh, Iran. Mohammad Taher Tahermohammad38@yahoo.com 200319475328460020266 200319475328460020266 No Saveh University of Medical Sciences, &Kaveh Industrial Estate Company Saveh, Iran. Fatemeh Zarei midwiferysaveh@gmail.com 200319475328460020267 200319475328460020267 No Department of nursing, college of nursing, Saveh Branch, Islamic Azad University, Saveh, Iran. Zahra Rezaie Shahsavarloo zahrarezaie23@yahoo.com 200319475328460020268 200319475328460020268 No Saveh University of Medical Sciences, &Kaveh Industrial Estate Company Saveh, Iran.