A retrospective study was performed to evaluate the results of medical management of primary vesicoureteral reflux (VUR) in infants and children. The charts of 105 patients (74 boys, 31 girls) with 167 refluxing ureters were reviewed. The age at diagnosis ranged from 3 days to 9.2 years (mean 1.3 +/- 1.9 years). The mean duration of follow-up was 2.4 +/- 1.5 years. We found that the patient's sex did not influence the fate of VUR and its complications. Patients whose reflux improved while being managed medically were younger than those who did not improve, and the younger the patient the sooner the reflux resolved. Improvement and resolution of reflux were also related to grade, and the lower the initial grading the sooner the reflux resolved. Spontaneous resolution rates of reflux were 92.3%, 76.2%, 61.7%, and 32.0% for grades I, II, III, and IV, respectively. No ureters with grade V reflux resolved without complications. The most common complications in our series were renal scarring and secondary obstructive uropathy.