We studied umbilical cord blood mesenchymal stem cells and compared mesenchymal stem cells derived from umbilical cord blood, adipose tissue, and skin. Umbilical cord blood mesenchymal stem cells were characterized morphologically, cytofluorometrically, and by their differentiation potential. Umbilical cord blood mesenchymal stem cells did not differ from cells isolated from adipose tissue and skin by the main parameters (by morphology, expression of surface markers, and differentiation potential). A specific feature of umbilical cord blood mesenchymal stem cells is their low count per volume of the initial material and very low proliferative activity.