The current study evaluated the cardioprotective activity of genistein in cases of doxorubicin-(Dox) induced cardiac toxicity and a probable mechanism underlying this protection, such as an antioxidant pathway in cardiac tissues. Animals used in this study were categorized into four groups. The first group was treated with sodium carboxymethylcellulose (0.3%; CMC-Na) solution. The second group received Dox (3.0 mg/kg, i.p.) on days 6, 12, 18, and 24. The third and fourth groups received Dox (3 mg/kg, i.p.) on days 6, 12, 18, and 24 and received protective doses of genistein (100 [group 3] and 200 [group 4] mg/kg/day, p.o.) for 30 days. Treatment with genistein significantly improved the altered cardiac function markers and oxidative stress markers. This was coupled with significant improvement in cardiac histopathological features. Genistein enhanced the Nrf2 and HO-1 expression, which showed protection against oxidative insult induced by Dox. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed substantial inhibition of apoptosis by genistein in myocardia. The study showed that genistein has a strong reactive oxygen species scavenging property and potentially (P ≤ .001) decreases the lipid peroxidation as well as inhibits DNA damage in cardiac toxicity induced by Dox. In conclusion, the potential antioxidant effect of genistein may be because of its modulatory effect on Nrf2/HO-1 signalling pathway and by this means exhibits cardioprotective effects from Dox-induced oxidative injury.