In the study 32 Wistar albino rats were divided into four group as control (Group Control, n=8), methotrexate (Group MTX, n=8), MTX + UDS (Group MTX+UDS, n=8) and Urtica dioica seed extract (UDS) (Group UDS, n=8). After the trial, blood and post-necropsy testicular tissue samples were taken. Histopathological examinations showed that methotrexate had an adverse impact on spermatogenesis by damaging testicles; however, such damages were substantially decreased in the Group MTX+UDS. In the immunohistochemical examinations glutathione peroxidase 1 (GPx1) immunoreactive areas was higher in the Group MTX + UDS compared to the Group MTX. Biochemical examinations revealed that the level of malondialdehyde (MDA), glutathione (GSH), glutathione S-transferase (GST) and catalase (CAT) enzymes levels statistically significantly differenced (p<0.001) in the Group MTX compared to the control, UDS and MTX+UDS groups. There were significant (p<0.05) differences the Group MTX from Group MTX+UDS. such as density, motility, dead-live sperm rate and abnormal sperm rate. Our study results showed that UDS prevented the damage occurred in the testicles according to histopathological, immunohistochemical, biochemical and spermatological findings.