Among heavy metals, lead is one of the common pollutants found in the environment and biological system. In the present study, streptozotocin-induced diabetic and normal non-diabetic male Wistar rats were given sodium selenite (1.0 mg/kg bw), lead nitrate (22.5 mg/kg bw) and sodium selenite plus lead nitrate (1.0 mg/kg + 22.5 mg/kg bw, respectively) through gavage. At the end of 4th week, malondialdehyde (MDA) levels, antioxidant enzyme activities [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST)], and histopathological changes of testes were investigated compared to the control group. No significant differences were observed between the control and sodium selenite treated groups. However, lead nitrate increased the levels of MDA, SOD, CAT, GPx and GST activities compared with the control group in diabetic and non-diabetic rats. Light microscopic analyses revealed that lead nitrate induced numerous histopathological changes in testis tissues of diabetic and non-diabetic rats. In the diabetic and nondiabetic sodium selenite plus lead nitrate treated groups, there were statistically significantly decreased MDA levels and antioxidant enzymes activities and mild pathological changes. As a result, sodium selenite significantly reduced lead nitrate induced testicular toxicity for both diabetic and non-diabetic rats.