This protocol describes isolation and characterization of CD133+ cells derived from normal human adult kidney. These cells express PAX-2, an embryonic renal marker, suggesting their renal origin. Renal tissue-derived CD133+ cells and clones of individual cells are capable of expanding, exhibit limited self-renewal and differentiate in vitro into epithelial or endothelial cells. Following subcutaneous implantation in SCID mice, the undifferentiated cells form tubular structures expressing renal epithelial markers.