The fetal urinary tract is routinely evaluated sonographically beginning in the first trimester with documentation of fetal bladder visualization. Fetal MR might be indicated to further clarify abnormalities found sonographically. The primary imaging modality for evaluation of the fetal kidney is US, which plays an important role in the detection of collecting system dilatation and parenchymal diseases that influence counseling and postnatal care. A commonly seen birth defect affecting the fetal kidney is pyelectasis. The significance of this finding has been extensively evaluated by a number of fetal imaging centers and will be presented in this review. Further topics of interest within the fetal genitourinary system include fetal renal parenchymal disorders and fetal bladder abnormalities. Characteristic imaging features, as well as developmental pathology and differential considerations, are discussed here.