Intrathoracic renal ectopia as a result of a congenital diaphragmatic hernia (CDH) is a rare congenital anomaly. We present a case in which the prenatal diagnosis of an ectopic intrathoracic kidney was made on routine anatomical survey at 28 weeks' gestation. Color doppler sonography imaging revealed the renal artery coursing into the infant's thorax and was consistent with CDH, but fetal MRI suggested an intact diaphragm. However, neonatal evaluation confirmed the diagnosis of intrathoracic kidney with posterior CDH, which was repaired without complication. In contrast to diaphragmatic hernia with liver or bowel herniation, infants with intrathoracic ectopic kidneys generally do well.