Embryonic and induced pluripotent stem cells, in addition to their capacity for self-renewal, are distinguished by their ability to differentiate into virtually any cell type. In recent years, a number of markers have been identified to distinguish these pluripotent stem cells. Some of these markers include: cell surface proteins and antigens such as, TRA-1-60, SSEA-1, SSEA-3 and SSEA-4; transcription factors such as OCT4, Nanog, c-Myc, SOX2 and KLF4; and others such as DNMT3B and Lin28. Such stem cell marker antibodies may prove to be useful tools in investigating pluripotent and embryonic stem cells.