Objective: To evaluate the effect of formononetin on type 2 diabetic cardiomyopathy. Methods: Diabetes was induced by feeding high-fat diet for 2 weeks and administration of 35 mg/kg of streptozotocin in rats. Formononetin was administered at 10, 20 and 40 mg/kg for 16 weeks once a day. Plasma glucose, lipid parameters, and cardiac markers in blood samples were measured. Body weight and relative heart weight were recorded. Hemodynamic parameters, oxidative stress parameters and silence information regulator 1 (SIRT1) expression in cardiac tissue were estimated. Histopathological changes in cardiac tissue were also observed. Results: Formononetin significantly reduced the levels of glucose, triglycerides, cholesterol, low density lipoprotein, creatine kinase-MB, lactate dehydrogenase and aspartate aminotransferase. In addition, formononetin significantly improved hemodynamic parameters, alleviated oxidative stress and increased SIRT1 expression. Conclusions: The study indicates that formononetin can improve hyperglycemia and hyperlipemia, reduce oxidative stress and increase SIRT1 expression. It can be a potential therapeutic agent for diabetic cardiomyopathy.