Background Stem cell transplantation has been shown to have beneficial effects on dilated cardiomyopathy. However,mechanism for stem cell homing to cardiac tissue in dilated cardiomyopathy has not yet been elucidated.Methods Mesenchymal stem cells were obtained from rat bone marrow, expanded in vitro, and labeled with 99mTc.Cardiomyopathy model was induced by doxorubicin in rats. 99mTc labeled cells were infused into the left ventricles in cardiomyopathy and control rats. Sixteen hours after injection, animals were sacrificed and different tissues were harvested to measure specific radioactivity. By use of real-time polymerase chain reaction and immunohistochemistry,a and protein expressions for stromal-cell-derived factor 1 in cardiac tissue were measured.Results Labeling efficiency of mesenchymal stem cells was (70.0±11.2)%. Sixteen hours after mesenchymal stem cell transplantation, the heart-to-muscle radioactivity ratio was increased significantly in cardiomyopathy hearts as compared to control hearts. Both a and rotein expressions of stromal-cell-derived factor 1 were up-regulated in cardiomyopathy hearts as compared with control hearts.Conclusion In dilated cardiomyopathy induced by doxorubicin up-regulated expression of stromal-cell-derived factor 1in heart may induce mesenchymal stem cells home to the heart.