Summary:The feasibility of usiug cord blood mesenchymal stem/progenitor cells(CB-MSPCs)to re-generate cardiomyocytes and the optimal inducing conditions were investigated.The CB mononuclearcells were cultured in low serum DMEM medium to produce an adherent layer.After expansion,theadherent cells were added into cardiomyocyte inducing medium supplemented with 5-azacytidine.Cardiogenic specific contractile protein troponin T staining was performed to identify the cardiomy-ocyte-like cells.The results showed that the frequency of CB-MSPCs clones in CB mononuclear cellswas 0.5×10~(-6) and about 1.3×10~7-fold expansion was achieved within 20 sub-cultivation.After car-diogenic induction,70％CB-MSPCs was differentiated into cardiomyocyte-like cells.It was indicat-ed that low serum culture could expand CB-MSPCs extensively and the expanded CB-MSPCs couldbe induced to differentiate into cardiomyocyte-like cells in high efficiency. Summary: The feasibility of usiug cord blood mesenchymal stem / progenitor cells (CB-MSPCs) to re-generate cardiomyocytes and the optimal inducing conditions were investigated. The CB mononuclear cells were cultured in low serum DMEM medium to produce an adherent layer. After expansion, theadherent cells were added into cardiomyocyte inducing medium supplemented with 5-azacytidine. Cardiogenic specific contractile protein troponin T staining was performed to identify the cardiomy-ocyte-like cells. The results showed that the frequency of CB-MSPCs clones in CB mononuclear cellswas 0.5 × 10 ~ (-6) and about 1.3 × 10 ~ 7-fold expansion was achieved within 20 sub-cultivation. After car-diogenic induction, 70% CB-MSPCs were differentiated into cardiomyocyte-like cells. serum culture could expand CB-MSPCs extensively and the expanded CB-MSPCs could be induced to differentiate into cardiomyocyte-like cells in high efficiency.