Objective: Doxorubicin (DOX) is a highly effective anti-cancer drug with limited clinical use due to its serious cardiotoxicity. Urtica dioica L. seeds (UD), have been widely used in folk medicine, particularly in the therapy for advanced cancer patients, possesses a potent anti-oxidant properties. The goal of present study was to investigate the cardioprotective effects of UD on DOX-induced cardiotoxicity. Method: The rats in the UD treated group were given intraperitoneally 2 ml/kg UD. To induce cardiotoxicity, 30 mg/kg DOX was injected intraperitoneally by a single dose and the rats were sacrificed after 48 h. Results: The present study revealed for the first time a protective role of UD against DOX-induced cardiotoxicity. UD therapy significantly protected against DOX-induced myocardial damage which was characterized by conduction abnormalities, vacuolization, inflammatory cell infiltration, hemorrhages, and myofibrillar disarrangement. As indicators of oxidative stress, DOX caused significantly increase lipid peroxidation and reduction in activities of antioxidant enzymes; superoxide dismutase, glutathione peroxidase, and catalase. UD treatment significantly attenuated DOX-induced oxidative injury. Conclusion: The present study showed that UD might be a suitable cardioprotector against toxic effects of DOX.