Fetal screening during maternal ultrasonography has changed the mode and age of presentation of congenital uropathies, particularly congenital obstructed megaureter. We studied 47 infants less than 8 months old with primary obstructed megaureter. Surgical correction in 42 patients with moderate to severe obstruction was performed at a mean age of 1.8 months in those detected prenatally and 3.8 months in those presenting after birth. All infants showed functional and structural urographic improvement with a mean followup of 2.3 years. Reflux was seen postoperatively in 8 patients, which subsided spontaneously in 3, continues to be followed in 2 and resulted in repeat reimplantation in 3. Five infants had mild obstruction, which was managed nonoperatively and 2 showed progressive obstruction, which required repair at ages 20 and 28 months. Repair of obstructed megaureters in early infancy improves renal drainage and offers the potential for preventing renal damage before the development of symptoms or infection. With proper attention to detail, excellent results may be achieved.