Background:Stress in infancy has dramatic effects on different systems, including the nervous system, endocrine, immune, reproductive and etc.Objective:The purpose of this study was to investigate the effects of extract of Iranian propolis (EIP) on ovarian tissue and oxidative stress in rats with maternal separation stress.Materials and Methods:48 immature female rats were divided randomly into six groups. 1) Control group, 2) Control group+saline, 3) Stress group, includes infants that were separated from their mothers 6 hr/day, the 4th, 5th and 6th groups consisted of infants who in addition to daily stress received 50, 100 and 200 mg/kg of EIP, respectively. Then serum corticosterone, 17-beta-estradiol, malondialdehyde, total superoxide dismutase, glutathione peroxidase and ferric reducing antioxidant power levels were measured. The ovarian sections were stained by H&E, PAS, and TUNEL methods and were studied with optical microscopy. Results:Stress increased the blood serum corticosterone levels and 17-beta-estradiol reduced significantly (p<0.001) and EIP prevented from this changes (p<0.01). EIP significantly increased the number of ovarian follicles, oocytes and oocytes diameter in neonatal rat following stress (p<0.01). EIP also significantly decreased the number of atretic follicles, TUNEL+granulosa cells, malondialdehyde levels and increased ferric reducing antioxidant power, total superoxide dismutase and glutathione peroxidase serum levels in neonatal rats following stress. The dose of 200 mg/kg EIP was more effective.Conclusion:This Study showed that the Iranian Propolis significantly could prevent oxidative stress and histopathological changes in the ovary of the neonatal rat the following stress.