T cells orchestrate immune responses and the ability to generate T cells from embryonic stem cells in a test tube could provide potentially limitless source of customized T cells for a variety of conditions including: cancer, infection and autoimmune diseases. In the past year of CIRM funding we have made progress toward this goal by comparing different culture conditions and distinct cell lines for their ability to generate blood cell types, including T cells in vitro. In the future, we plan to combine studies in humanized mouse models with in vitro approaches to overcome the bottleneck generating T cells from stem cells.