Abstract: AIM:To study the feasibility and safety of myocardial syringe for transendocardial delivery of autologous bone marrow mesenchymal stem cell (MSCs) into swine-infarcted hearts. METHODS: The left anterior descending coronary artery of swine was occluded for 60 min by coronary balloon to establish the myocardial infarction model. After 2 weeks, autologous bone marrow MSCs were transplanted into myocardium using myocardial syringe. Eight weeks later, animal hearts were harvested for pathological examination by immunofluorescence. RESULTS: Four swine models were successfully established and one died due to ventricular fibrillation during coronary artery occlusion. Left ventricular contrast imaging localized the endocardium-injected points. Immunofluorescence further demonstrated the survival of the injected cells in the host’s heart. CONCLUSION: Catheter-based transendocardial delivery of bone marrow MSCs into myocardium is feasible and safe.