Calycosin (CC) is a phytoestrogen, isolated from Radix astragali a well-known Chinese herb and used for treating various pathological conditions. The current study was projected to elucidate the cardio-preservative property of CC in isoproterenol (ISO) induced cardiac injury model (MI) in rats. Male SD rats (n=48) were equally divided into 4 groups which include normal rats (Control; n=12), ISO-MI rats (n=12) which were injected with 85 mg/kg of ISO for 2 days. ISO+CC rats (n=12) were pre and post-treated with CC (30 mg/kg). CC alone rats (n=12) were injected with only CC (30 mg/kg). Pre and post-treatment with CC after and before ISO exposure showed strong cardioprotective property through significant reduction (p<0.05) in the mean values of cardiac infarct size, serum cardiac markers, inflammatory markers, apoptotic markers, lipid peroxidation (oxidative stress) by improving antioxidant status as well as reversing all those histopathological changes. Based on the results, we suggest that CC might be useful against MI if consumed along with standard MI medication to lower cardiac dysfunction and its related complications. However, further studies are needed to justify the above statement.