The objective of this study is to investigate the effects of nimesulide on ketamine-induced ovarian and uterine toxicity by biochemical and histopathological examinations. Ketamine is an anesthetic agent whose use leads to overproduction of catecholamines. Nimesulide is a cyclooxygenase-2 inhibitor, which has also been reported to exert a significant antioxidant effect. Wistar albino female rats were randomly divided into three groups as follows: ketamine group (60 mg/kg), ketamine (60 mg/kg)+nimesulide (50 mg/kg) group, and a healthy control group. Then, the biochemical levels and histopathological findings in the ovaries and uteri of the rats were examined for malondialdehyde, myeloperoxidase, total glutathione and superoxide dismutase. The study demonstrated that, in the uterine and ovarian tissues of rats that have been administered ketamine, there was a decrease in the levels of total glutathione and superoxide dismutase, while malondialdehyde and myeloperoxidase was increased: however it was observed that these ratios were reversed in the ketamine+nimesulide group. It was also proved that the negative effects of ketamine can be corrected with nimesulide when the myometrial and endometrial thicknesses are compared. Antioxidants such as nimesulide may protect against the damage caused by ketamine to the genital organs in young women.