US screening in pregnancy is the most useful and reliable examination for prenatal diagnosis. It permits the identification of a larger proportion of urinary tract malformations (UTM). The present study was undertaken to assess the diagnostic accuracy of antenatal US in risk population. The authors report 18 cases of fetal urinary abnormalities revealed by US. In 17 infants the prenatal diagnosis was confirmed precisely revealing: hydronephrosis-2 cases, VUR III-V degree--5 cases, multicystic kidney--3 cases, megacyst--3 cases, posterior urethral valves and VUR-2 cases and polycystic disease--2 cases. A false positive diagnosis in utero occurred in one case. There were no false negative diagnoses. US is a valuable tool in antenatal diagnosis of UTM.