CD34 is a glycosylated transmembrane protein and represents a well-known marker for primitive blood- and bone marrow-derived progenitor cells, especially for hematopoietic and endothelial stem cells. Although the biological functions of CD34 are largely unknown, recent data suggest that CD34 is involved in maintenance of the progenitor cells in a phenotypically undifferentiated state. PromoCell offers CD34+ Progenitor Cells from the cord blood of healthy donors. The CD34+ Progenitor Cells contain two main cellular subpopulations, hematopoietic and endothelial progenitor cells. Therefore, CD34+ Progenitor Cells are suitable for a series of studies, e.g. directed differentiation into more committed types of blood cells and endothelial lineages.