Diabetes mellitus is associated with diabetic impairment of uterine function, ultimately leading to reduced fertility. Its etiology may involve oxidative damage by reactive oxygen substances, and protection against this damage can be offered by antioxidant supplementation. In the present study, the effects of a vitamin E-plus-selenium (VESe) combination on lipid peroxidation (MDA) and the scavenging enzyme activity in the uterine endometrium of streptozotocin (STZ)-induced diabetic rats were investigated. Twenty-four female rats were equally divided into three groups as follows: group I (control); group II (diabetic); group III (diabetic + VESe), STZ + vitamin E (60 mg/kg over 1 day) + selenium-treated (Na2SeO3, 1 mg/kg over 1 day). After 4 weeks of receiving the VESe treatment, endometrium samples were taken from the uterus. Although the VESe treatment decreased the MDA and blood glucose levels in the STZ group, the observed values remained significantly higher than in the controls. Catalase, superoxide dismutase, and glutathione peroxidase activities and body weight gain were significantly (p < 0.01) lower in STZ groups as compared to control group, whereas their activities were (p < 0.01) increased by VESe treatment. However, there was no significant difference on body weight gain and uterine weights between control and STZ + VESe groups. In conclusion, the endometrial complications caused by oxidative stress, and the abnormal blood glucose levels in diabetic of rats, can be alleviated by strengthening the physiological antioxidative defense through the administration of vitamin E and Se.