This retrospective review identified 122 cases with a prenatal diagnosis of genitourinary anomalies and categorized them into parenchymal and collecting system abnormalities. Comparisons were made between the anatomical groups for indications for ultrasound, average gestational age at positive and negative renal ultrasound diagnosis, amniotic fluid volume and pregnancy outcome with postnatal diagnosis. The results indicated that parenchymal abnormalities were detected earlier in gestation than collecting system anomalies. Additional fetal anomalies were more often present in the parenchymal group. Chromosome abnormalities were present in 5% of the urinary tract abnormalities. Parenchymal abnormalities were more likely to have oligohydramnios and a higher mortality rate.