Objective:To study the differentiation potential of human umbilical cord mesenchymal stem cells into osteogenic,adipogenic,myocardiogenic and endothelial cells. Methods:The human umbilical cord mesenchymal stem cells were cultured and differentiated in the osteogenic,adipogenic,cardiomyogenic and endothelial medium. At the end of the culture,the cells were stained with Von Kossa or Oil red-O solution to reveal osteogenic and adipogenic differentiation. Immunocytochemistry and immunofluorescence were performed to investigate differentiation of the cells to cardiomyocytes and endothelial cells. Results:The human umbilical cord mesenchymal stem cells were positive for Von Kossa staining and have the ability to accumulate different amounts of lipid vacuoles after cultured in osteogenic and adipogenic medium. Immunocytochemistry showed that differentiated cells were strongly stained with cardiac sarcomeric α-actin and cardiac myosin after 5-azacytidine treatment. Immunofluorescence studies confirmed their endothelial phenotype with expression of known endothelial cell markers including CD31 and CD34 after VEGF treatment. Conclusion:Our results demonstrated that human umbilical cord mesenchymal stem cells have the ability to differentiate into osteogenic,adipogenic,myocardiogenic and endothelial cells.