Objective: Hyperthermia is the condition of the body temperature rising at 41°C or more. Heat stres on ductus epididymis leads to abnormal spermium production and spermatogenesis. Hyperthermia induced oxidative stres and apopitosis can be blocked by superoxide dismutase (SOD). In this study we aimed to determine the protective effects of SOD on ductus epididymis at hyperthermic conditions by using apoptotic and oxidative stress markers Methods: Wistar Albino male rats were divided into seven groups. Every group has 6 rats. Control group had set for 20 minutes in a pool which was 22°C temperature. On the second, third, fourth groups NaCl + catalase were applied one hour before hyperthermia, and then the rats were abondoned in 42°C water bath for 20 minutes. After that tissue were taken at 6th, 24th, 72th hours respectively. On the fifth, sixth and seventh groups NaCl + catalase + SOD was applied one hour before hyperthermia and then the rats were abandoned in 42" C water bath for 20 minutes. After hyperthermia for 20 minutes tissues were taken at 6th, 24th and 72 th hours respectively. In order to determine apoptosis caused by hyperthermia, removed tissues were subjected to indirect immunohistochemical method with HSP-70 primary antibodies to detect impact on Caspase 9, Caspase 8 and Caspase 3 protein structures. Results: Morfologically abnormal spermium including lumens show positive Caspase-3 reaction. This was accepted as an indicator of abnormal spermiums, which were caused by effects of hyperthermia, can reach ductus epididymis. It was also remarkable that some areas, round spermatide heads directed into epithelium an even intruded into stereocilias. It was thought that, this direction can be caused by a mechanism which is organized by principle cells, which were not destroyed in Sertoli cells. It was observed that, for all caspases, SOD application is reducing the immunreactivity in parallel to time. Conclusion: The scrotal temperature elevation shows its harmfull effects on epididymis, but the SOD application may suppress apoptosis in parallel to time by increasing HSP70 level. ©Copyright 2013 by Gazi University Medical Faculty.