The focus of this review is the normal and abnormal development of the kidney and lower urinary tract; for convenience, we will refer to the whole system as the renal tract. The content represents a convergence among the clinical disciplines of histopathology, nephrology, and urology as well the basic sciences of developmental biology and molecular genetics. The story has considerable clinical relevance since diverse renal tract malformations are increasingly detected on fetal ultrasound screening and constitute major causes of chronic renal failure necessitating dialysis and kidney transplantation in children. Evidence is emerging that at least some of these disorders have a defined genetic basis; in others, an abnormal embryonic, or even maternal, environment may contribute to the pathogenesis. This field of study is frequently updated, with new discoveries being made almost every week. Hence this review can not be exhaustive or definitive, but instead highlights some specific areas of interest.