摘要:Introduction: Diabetes malady because of making oxidative stress has an important role in causing the metabolism damages. The aim of this study was to assess the effect of melatonin with regard to its anti oxidant attribute for treatment of testicular damage of diabetes. Methods: In this research, 24 male vistar rats with average weight of 200-220g were choosen and divided into 3 groups of control, diabetic and treatment. Diabetes group was induced by Sterptozotosin (STZ) injection(55mg/kg), and treatment group, (diabetic + melatonin), after two months of becoming diabetic received melatonin pill with 10mg/kg dose of it in gavage way during 5 weeks. At the start of the fifth week, the blood samples were taken from the rats and biochemical and blood hormones invoices and also testicle sections were histologically evaluated. Results: Diabetes through producing oxidative stresses and producing of free radicals decreases spermatogoni and sertoly cell and also decreases spermatogenesis and sperm functions. Diabetic also decreases quantity of insulin and testosterone hormones. Melatonin administration increases amount of plasma insulin and testosterone hormone that significantly decreases the produced morphologic changes. Conclusion: Melatonin can prevent and cure oxidative stresses and also it can be a cure for testicular damages resulting from diabetes.