Abstract: Objective To assess the value of ultrasound in diagnosis of congenital renal malformations. Methods The records of obstetric ultrasound examinations were reviewed in all the pregnant women admitted in Alta Bates Perinatal Diagnostic center (Oakland, California, USA) during 5 years. Results Ultrasound examination identified 58 cases of congenital renal malformations of different kinds, including 4 cases of renal agenesis, 8 multicystic dysplastic kidney, 5 cystic renal dysplasia with obstructions, 6 renal and ureteral duplications, 6 ectopic kidneys, 18 hydronephroses, 3 autosomal recessive polycystic kidney diseases, 2 autosomal dominant polycystic diseases, 1 Finnish-type congenital nephrosis, 3 Meckel-Gruber syndromes, and 2 Beckwith-Wiedemann syndromes. Different renal malformations had different ultrasound findings that correlated to abnormalities in embryonic developments. Conclusions Urinary tract abnormalities have a profound effect on pregnancy outcome, especially when associated with oligohydramnios. Many urinary anomalies can be readily detected and diagnosed by ultrasound, which provides a useful modality in diagnosis of fetal congenital renal malformations. Clear understanding of the causes of these abnormalities facilitates prognostic evaluation and clinical decision on the treatment protocol.