Human embryonic stem cells (hESCs) and patient-specific human induced pluripotent stem cells (hiPSCs) are valuable reagents for studying the earliest stages of hematopoietic genesis and for modeling the developmental basis of hematologic disorders, and they may also have the potential for generating an unlimited supply of autologous transplantable hematopoietic stem cells. We have previously described the development phases of hematopoiesis that arise from differentiated hESCs using a human embryoid body (hEB) culture system. This hEB system produces hematopoietic and endothelial progenitors through a hemangioblast intermediate. In this chapter, we describe a modified and optimized version of this hEB system that generates high frequencies of multipotent CD34+ CD45+ hematopoietic progenitorsviaemploying hEB hematopoietic differentiation followed by adherent hemogenic endothelium generation. Multipotent hematopoietic progenitors can be reproducibly generated in robust amounts with this differentiation system from a wide variety of hiPSC or hESC for biochemical, transcriptomic, epigenetic,
