fa Original Article Original Article - <strong>Background:</strong> Considerable attention is focused on effects of electromagnetic field (EMF) and its increasing use in everyday life. Appliances and various equipments are sources of electromagnetic fields with a wide-range of technical characteristics.<br> <strong>Objective: </strong>In this study we investigated the effect of EMF (50 Hz, 0.5 mT) on epididymis and deferens duct in mice.<br> <strong>Materials and Methods: </strong>30 BALB/C mice were selected and divided into three groups (control, sham and experimental). While control and sham groups were not exposed to EMF, the experimental group was exposed to EMF (50 Hz, 0.5 mT) 4 hours a day, 6 days per week and for 2 months. At the end of 2 months, the mice were sacrificed, dissected and samples from epididymis and vas deferens in all groups were taken and processed for light microscopic studies. 40 microscopic fields from each group were randomly selected. The diameters and the height of epithelial cells of epididymis and deferens duct in 3 groups were measured and compared using statistical methods.<br> <strong>Results: </strong>The data showed that the mean diameter of epididymis and deferens duct in EMF group was significantly decreased compared to the control group (p=0.001). The height of epithelial cells in epididymis and deferens duct in EMF group was considerably reduced compared to the control and sham groups (p=0.001). In addition, the weight of testes in EMF group was significantly decreased compared to the control and sham groups (p<0.007). <strong>Conclusion: </strong>It could be concluded that the exposure to EMF leads to detrimental effects on male reproductive system in mice as seen by a decrease in diameter of reproductive ducts, the height of epithelial cells and weight of testes. Electromagnetic field, Mouse, Epididymis, Deferens duct. 85 90 http://ijrm.ir/browse.php?a_code=A-10-549-216&slc_lang=fa&sid=1 Farzad Rajaei farzadraj@yahoo.co.uk Yes Infertility Research Centre, Faculty of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran Mehdi Farokhi No Department of Anatomy, Faculty of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran Nazem Ghasemi No Department of Anatomy, Faculty of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran Ali Asghar Pahlevan No Basic Sciences Research Centre, Faculty of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran