Of 222 infants with a urinary tract abnormality detected antenatally 30 male and 9 female patients (64 renal units) were found to have primary vesicoureteral reflux. Grade of reflux was predominantly severe, with grade III or higher noted in 83% of the patients. Prenatal and postnatal ultrasound failed to detect any abnormality in 29 refluxing units (45%) discovered contralateral to the known abnormal system, although 19 had grade III or higher reflux. Of the 64 refluxing units 8 underwent primary ureteral reimplantation, 12 were lost to followup and 44 were managed conservatively for a mean of 3.3 years. Reflux ceased in 61% of the cases, improved in 14% and remained unchanged in 23%. In only 1 unit did the grade of reflux increase. Documented urinary tract infection occurred in 6 of the 39 reflux patients. Dimercaptosuccinic acid renography performed in 21 infection-free patients demonstrated global reduction in renal parenchyma in 4 units, focal parenchymal defects in 3 and normal function in 14. Conservative postnatal management of fetal vesicoureteral reflux is justified. Global and focal parenchymal changes can occur in the kidneys of infants with reflux despite the absence of urinary tract infection.