We have made substantial progress towards increasing our knowledge about early kidney development, identified new ways to differentiate human embryonic stem cells (hESC) to kidney lineages, and explored the use of these and other related kidney cells to study repopulation of the kidney. In order to obtain the necessary cell types for regenerative medicine purposes, differentiation of hESC must follow developmental pathways and recapitulate normal development, and our studies have brought us closer to this goal. Investigations have supported that expression of early developmental markers provides a useful and efficient method to direct differentiation of hESC towards renal lineages. The results of these studies have established cell culture conditions that ensure we can consistently obtain the quantity of differentiated hESC needed for transplantation into developing and damaged kidneys. Significant progress has also been made in developing new and effective techniques for labeling cells for in vivo imaging, and monitoring the labeled cells post-transplantation using positron emission tomography (PET). We have collected sufficient quantities of cells in culture, and identified effective methods to label the cells without altering viability, proliferation, or function. We have also shown that these same cell populations can be used for transplantation into developing kidneys, and that the cells persist post-transplant over time and can be identified using PET. This strategy has allowed us to precisely document cell location post-transplantation in vivo, demonstrated that post-transplant viability was maintained, and shown that the cells did not migrate to other anatomical sites.