Background and Objective: Doxorubicin (DOX) is an effective anticancer drug. It has been shown that a short-term exercise performed prior to DOX-treatment has no effect on cardiotoxicity in young rats. In the present study, old and young rats were evaluated to determine the protective effects of pre-treatment with short-term exercise on DOX-induced oxidative damage in cardiac tissue.Methods: Forty-eight male Wistar rats were randomly divided into two groups of young and old, and later divided into three sub-groups of young+DOX, young+training+DOX, young+training+salin, old+DOX, old+training+DOX and old+training+salin. The training protocol included treadmill running for 25-39 min/day at 15-17 m/min, 5 days/week for three weeks. All treatments were carried out 24h after the last exercise bout. The rats were sacrificed 48h after DOX administration.Results: Although DOX injection significantly affected the cardiac tissue of old rats compared to young rats, pretreatment with endurance training in DOX-treated rats caused an increase in Heat shock protein (3.02% vs. 23.36) and superoxide dismutase (30.12% vs. 31.12), and a decrease in malondialdehyde (10.92% vs. 19.60) in both old and young rats.Conclusion: Although DOX-induced production of free radicals and cardiotoxicity in aged rats is more than that in young rats, the short-term aerobic exercise reduced the damaging effects of free radicals in the old rats more than in young ones. The concentration of antioxidant enzymes also increases with exercise in the old rats compared to young rats.