OBJECTIVE: Myocardial infarction (MI) is one of the most important causes of death. MI-related tissue loss and cardiac remodeling may result in heart failure. Intramyocardial injection of mesenchymal stem cells derived from adipose tissues, in acute MI animal models, has shown promising regenerative capabilities. This study aimed to investigate the myocardial regenerative capacity of epicardial adipose tissue-derived mesenchymal stem cells (ADSCs) in a rabbit model of MI. MATERIALS AND METHODS: A rabbit model of MI was performed in three groups: A sham- operated group, a control group, and a treatment group. MI was induced by coronary artery ligation via thoracotomy in the first operation. Four weeks after the first operation, intramyocardial injections of phosphate-buffered saline (PBS; control group) or ADSCs (10×106 in 100 μL; treatment group) were performed in the peri-infarct zone. Four weeks after the second operation, rabbits were sacrificed for further analysis. RESULTS: A significant increase in ejection fraction (p