Objective To isolate mesenchymal stem cells(MSCs)from human umbilical cord and investigate the basic biological characteristics.Methods Human umbilical cord mesenchymal stem cells(hUCMSCs)were separated from culture of tissue adherence and the biological characteristics,including morphologic appearance,surface antigens,growth curve,cell cycle,cytogenetic features,differentiation potential and gene expression,were investigated.Results After two weeks of incubation,fibroblast-like cells appeared to be dominant.During the second passage the cells presented a homogeneous population of spindle fibroblast-like cells.Flow cytometry analysis revealed that CD29,CD44,CD95,CD105 and HLA-I were expressed on the surface of cells,but there was no expression of hematopoietic lineage markers,e.g.,CD34,CD38,CD71 and HLA-DR.Chromosomal analysis showed the cells kept normal karyotype.The cell cycle at the third passage showed the percentage of G0/G1,G2/M and S phase were 88.86%,5.69% and 5.45% respectively.The assays in vitro demonstrated the cells exhibited multipotential differentiation into osteogenic and adipogenic cells.Both BMI-1 and nucleostemin genes,expressed in adult MSCs from bone marrow,were also expressed in hUCMSCs.Conclusion Here we show the umbilical cords may be a novel alternative source of human MSCs for experimental and clinical applications,which almost have the same biological characteristics of human adult MSCs. Objective To isolate mesenchymal stem cells (MSCs) from human umbilical cord and investigate the basic biological characteristics. Methods Human umbilical cord mesenchymal stem cells (hUCMSCs) were separated from culture of tissue adherence and the biological characteristics, including morphologic appearance, surface antigens, growth curve, cell cycle, cytogenetic features, differentiation potential and gene expression, were investigated. Results after two weeks of incubation, fibroblast-like cells appeared to be dominant. Embracing the second passage the cells presents a homogeneous population of spindle fibroblast-like cells. Flow cytometry analysis revealed that CD29, CD44, CD95, CD105 and HLA-I were expressed on the surface of cells, but there was no expression of hematopoietic lineage markers, eg, CD34, CD38, CD71 and HLA- DR. Chromosomal analysis showed the cells kept normal karyotype.The cell cycle at the third passage showed the percentage of G0 / G1, G2 / M and S phase were 88.86%, 5.69% and 5.45% respectively ly.The assays in vitro demonstrated in cells multipotential differentiation into osteogenic and adipogenic cells. Both BMI-1 and nucleostemin genes, expressed in adult MSCs from bone marrow, also also expressed in hUCMSCs. Confluence Here we show the umbilical cords may be a novel alternative source of human MSCs for experimental and clinical applications, which almost have the same biological characteristics of human adult MSCs.