Background: Selenium supplementation could be effective on reproductive function, however, its effect on serum Osteopontin (OPN) level in Polycystic Ovary Syndrome (PCOS) is not studied yet. Aim of Work: The present study examines the effect of selinum on ovarian structure and function, in addition to its effect on OPN level in letrozole-induced PCO rat model. Material and Methods: Thirty albino rats were included in the study and divided into 3 groups: Group (I): Normal control group, Group (II) PCOS group and Group (III): PCOS treated group with intra peritoneal (i.p.) sodium selenite (0.3mg/kg) for 14 days after PCO induction, which was induced by oral letrozol (1mg/kg) daily for 21 consecutive days. At the end of the experiment physical parameters (body weight, duration of oestrous cycle, ovarian and uterine weights) were estimated, metabolic parameters (glucose, insulin and calculated HOMA-IR), hormonal profile (total testosterone, 17 p - estradiol, progesterone, FSH and LH), inflammatory mediators (OPN and C-Reactive Protein (CRP)), and finally macro anatomical and micro morphological studies of the ovaries were done. Results: There was a significant increase in serum FSH,LH, testosterone, CRP, OPN, body weight and duration of esterous cycle with significant decrease in estradiol, progesterone level and uterine weight accompanied by appearance of multiple ovarian cysts and disappearance of corpus luteum in histological studies in Group II. However, selinum treatment for fourteen days reversed the above mentioned findings except for body weight. Moreover, OPN showed a significant positive correlation with FSH, LH and CRP. While it showed a significant negative correlation with estradiol and progesterone in both Group II and III. Conclusion: Treatment with selinum exerts beneficial effects in PCOS rats which might be due to its antiinflammatory properties.