We have retrospectively studied 163 newborns referred to us between 1986 and 1990 for sonographic diagnosis of intra-uterine upper urinary tract enlargement. All were studied by paediatric radiologists on days 5th or 6th after birth by means of sonography and voiding cystourethrogram (VCU). Fifty percent had also IVP. No urinary tract disease could be found in 44 children, obstructive uropathy or cystic disease were diagnosed in 58 children and 61 patients had vesico-ureteric-reflux (VUR). They form the basis of the present report. There was a male-to-female ratio of 3.3 to 1. Neonatal ultrasonography was normal in 11 cases, 42 had pyelectasia (bilateral in eight cases) and eight had ureterohydronephrosis (bilateral in seven). VUR was bilateral in 28 cases, right in 16 and left in 17. Out of the 89 refluxing units, VUR grade was I in 11, II in 16, III in 24, IV in 14 and V in 23. There was intra-renal reflux in 17 units. Some other form of urinary tract disease was detected in 29 babies (47.5 per 100). Twenty-eight patients were operated upon and the remaining are under long-term urinary antisepsis with only five episodes of infection. The considerable proportion of false negatives for VUR in neonatal ultrasonography (30 per 100) and the high grade of some of these cases lead us to strongly advise routine VCU for patients with intra-uterine urinary tract dilatation.