Hematopoietic Stem Cells (HSCs) are multipotent adult stem cells that self-renew and differentiate into different lineages of blood cells. Because HSCs can replenish virtually all blood types, they have much potential in medical treatments of cancer and other immune diseases. In identifying HSCs, certain markers have been reported. These include CD34, CD38, CD90, CD133, CD150, CD48, VCAM1, SSEA-4, Sca-1, CD45, CD134, CD244, CD44, and Endoglin. Antibodies detecting these markers may aid in the investigation of HSCs and its related research areas. It should be noted, however, that new findings typically arise that may report a new marker, or question existing ones.