Background: Generation of free radicals and oxidative stress are a major contributorto diabetes. These factors lead to the development of diabetic testicles disorders.Objective: In this study, the protective effect of vitamin E on functional disordersassociated with diabetes induced oxidative stress in male reproductive systems hasbeen investigated.Materials and Methods: Thirty-three adult male Mice were divided into control,diabetic, and untreated diabetic groups. Streptozotocin was used to induce diabetes.In the treated group, vitamin E was given to the Mice intraperitoneally for 30 days.Then, animals were anesthetized and sacrificed. Animal testicles were isolated andhomogenized in phosphate buffer and used for measuring sperm count, motility andsurvival of sperm, MDA concentration and antioxidant capacity (TAC). Apoptosis wasalso performed with the TUNEL test.Results: The results of reduction (12.03±98.11) TAC, MDA concentration (–28.5±2.58),sperm motility (unstable sperma= 86.4±7.48), sperm count (171.51), Sperm morphology(natural morphology= 49.69±31.93) and abnormal morphology (9.77±49.7)with increased oxidative damage. These changes were statistically significant incomparison with the control group for all variables other than MDA (p= 0.05). Treatmentof vitamin E diabetic Mice improved the ability of antioxidants to prevent oxidativedamage in the testicles, restore the sperm movement, and increase the number ofnormal sperm as well as TAC. The level of apoptosis in the treated group has decreasedcompared to the untreated group.Conclusion: Vitamin E protects the reproductive system against diabetes mellitus.Therefore, it was concluded that vitamin E may be a suitable agent for protecting thesperm and testicular parameters against undesirable effects of diabetes.