With the attractive potential therapeutic uses of both endothelial and hematopoietic cells in medicine, much attention has been focused upon the differentiation of embryonic stem (ES) cells into mature cells of these lineages. In this chapter, we present a culture system that has successfully generated both complex endothelial structures and mature hematopoietic cells from undifferentiated ES cells in vitro. The simplicity of this system allows detailed analyses of factors and developmental steps essential in the generation of vascular structures and mature hematopoietic cell types.
