An in vitro niche in which nephron progenitor cells (NPCs) isolated from mouse embryonic kidneys or human embryonic stem cells can be propagated has been developed by modulating FGF, BMP, and WNT signalling pathways. The technique allows for NPCs to be expanded up to one billion-fold and for the cells to be induced to form tubules that express nephron differentiation markers. The single cell cultures derived from cells within the NPC compartment exhibited phenotypic variability, and the developmental age of the NPCs did not correlate with propagation capacity.