Background: Intra uterine devices (IUDs) are among the most commonly used contraception methods around the world. The most common form of IUDs used in Iran, is IUD Copper T-380A.As recently there is great emphasis on the role of blood zinc levels on general health conditions, this study was performed to assess the effects of IUD T-380-A insertion on zinc and also copper serum levels.Materials and Methods: This was a prospective cohort study performed on 66 women clients attending Health Centers of Tehran.After giving adequate explanations about the study and obtaining the clients’ written consent, a blood sample was obtained before and 3 months after the insertion of a Copper T-380-A IUD, and serum levels of copper and zinc were measured by an auto analyzer Instrument in a single laboratory. None of the participants were anemic, and so none received ferroussulfate complements during the study. The statistical software and methods used were: SPSS version 16 and paired sample t tests.P<0.05 were considered significant.Results: There were significant elevations in both copper (166.70±32.31 vs.153.74±39.29 mg/dl) and zinc (105.47±16.13 vs.90.76±16.22 mg/dl) mean serum levels, 3 months after IUD insertion.Conclusion: In this study, there was a slight increase in copper serum levels-but not reaching toxic levelsafter IUD insertion, which was expectable, as the IUDs contained copper. As zinc has an inverse relationship with copper in the body, the excess of copper can be a concern. In this study this concern was removed, due to not the decrease, but the remarkable increase of serum zinc levels after IUD insertion. This finding needs further investigations in larger studies with different study settings, to evaluate the exact health risks or benefits of IUDs.