Ninety cases of genitourinary tract anomalies diagnosed before birth are reviewed. Factors stressed are the relationship between the site of the anomaly and the time of the diagnosis. Low level urinary tract obstructions tend to be diagnosed early, high level lesions late. Overall, the diagnostic accuracy was 88% with urethral obstruction being most often accurately diagnosed (19 of 20 cases). The frequency with which associated anomalies are found is stressed as is the lack of correlation between amniotic fluid volume and high or mid level obstructions. Ovarian cysts are usually diagnosed late in gestation and are seldom associated with other anomalies.