Diclofenac sodium (DS) is a non-steroidal anti-inflammatory drug (NSAID). DS exerts its effect by binding to cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) and preventing the conversion of arachidonic acid into pro-inflammatory prostaglandins by chelation. The aim of this study was to investigate the effect of DS on mRNA expressions of both reproductive tissue antioxidant enzymes and serum reproductive hormones in female rats. A total 28 female albino Wistar rats were randomly divided into 4 groups (Control, I, II and III). The control group received no treatment. Groups I-II-III were injected intramuscularly with a dose of 2.5 mg/kg DS once a day for 3 days. After the 3rd DS application, Group I (2 hours), Group II (48 hours) and Group III (7 days) were sacrificed. Superoxide dismutase1 (SOD1), glutathione-peroxidase (GPx), catalase (CAT) in uterine and ovarian tissues, and serum microsomal prostaglandin E synthase-2 (mPGES-2), estrogen receptor α(ERα)-β(ERβ) and progesterone (PR) analyses were performed by PCR method. CAT decreased in uterus and ovary in all treatment groups (P<0.001). Uterine SOD1 showed increased in groups I-II and decreased in group III (P<0.001). Ovarian SOD1 increased in group I, decreased in groups II-III (P<0.001). ERα, ERβ increased in the treated groups I-II-III (P<0.001). PR increased in groups I-III and decreased in group II (P<0.001). mPGES decreased in group I and increased in groups II-III (P<0.001). In conclusion, it is observed that DS use causes negative changes in mRNA expression of some antioxidant enzymes and hormones in the reproductive system of female rats. It is recommended that the mating of female rats be postponed for seven days following the administration of DS, a common practice in human and animal health.