BACKGROUND Prenatal diagnosis of urological anomalies is a standard procedure nowadays. The aim of this study was first to define the frequency of urinary tract anomalies in the selected patients in a level III center for prenatal diagnostics and therapy. The second aim was to show the accuracy of prenatal diagnosis in the special groups of obstructive uropathies. METHODS Postnatal diagnoses were used for control of the prenatal findings. In the 12-year retrospective study, we analyzed 21 616 pregnancies scanned for fetal anomalies. In 1 574 fetuses pediatric surgical anomalies were diagnosed. Out of 1 077 follow-ups 618 patients with urinary tract anomalies were found. RESULTS It could be shown that prenatal ultrasound has a high sensitivity for the diagnosis of obstructive renal tract anomalies. The diagnosis of subpelvine obstruction and muticystic kidney dysplasia can be made with an accuracy of 97 and 98 %. The therapeutic relevance of the diagnosis "isolated hydronephrosis" increases up to 60 % when mild dilatation is neglected. False negative scans for urinary tract anomalies are low at 10 %. CONCLUSIONS Hence, prenatal ultrasound for urinary tract anomalies is a method of high sensitivity. The therapeutic relevance is rather high. The most important question is to find all those patients who need a postnatal therapeutic approach immediately.