Abstract： Objective To investigate the value of MRI in the prenatal diagnosis of abnormal fetal kidneys. Methods From December 2014 to March 2016, 51 women underwent MRI and were confirmed as having fetuses with abnormal fetal kidneys when follow up. Their clinical and MRI profiles were analyzed retrospectively, including MRI manifestation, the fetal kidney signal intensity of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC). The signal intensity of DWI and ADC of the abnormal kidney and the normal opposite kidney, and those of the normal and abnormal kidneys in different individuals were compared. The accuracies of MRI and ultrasound in evaluating abnormal fetal kidneys were also compared. Results MRI could accurately demonstrate the morphological features of abnormal fetal kidneys. There was no statistically significant difference between DWI signal intensity and ADC value of the abnormal kidney[368 ± 125,(1.516 ± 0.420)× 10-3 mm2/s] and the normal opposite one[410 ± 125,(1.362 ± 0.251)× 10-3 mm2/s], P values were 0.165 and 0.184,respectively. The DWI signal intensity of normal kidneys(401 ± 124)was higher than that of renal cysts(182 ± 40, P<0.01), and the ADC value of normal kidneys[(1.306 ± 0.252)× 10-3 mm2/s] was lower than that of renal cysts[(2.912 ± 0.235)× 10-3 mm2/s] and multicystic dysplastic kidneys[(1.870 ± 0.654)× 10-3 mm2/s], P values were<0.01 and 0.045, respectively. The diagnostic accuracy of MRI and prenatal ultrasound for abnormal fetal kidneys were 94%(63/67)and 85%(57/67), respectively. However, there was no statistical difference between the two methods (P=0.070). Conclusion MRI have an important role in the prenatal diagnosis and evaluation of abnormal fetal kidneys.