Molecular regulation of renal development has been an area of intense study over the last decade. Below we have highlighted critical studies demonstrating the importance of specific genes and gene families at particular stages of renal development; however, the list is by no means complete and readers are referred to some recent reviews which deal with this subject in greater depth (Clark and Bertram 1999; Clark et al. 2001; Pohl et al. 2000; Davies 2001; Bouchard 2004; Cullen-McEwen et al. 2005; Costantini and Shakya 2006; Schmidt-Ott et al. 2006; Boyle and de Caestecker 2006).