Vesicoureteral reflux (VUR) is one of the most common urinary tract anomalies in children and causes renal damage and studies focusing on the effect of VUR on renal function are rare. We recruited 35 primary VUR patients with recurrent urinary tract infection (UTI) and 10 non-VUR patients with recurrent UTI. Contrast-enhanced voiding urosonography (ceVUS) was performed for VUR grading, and renal dynamic imaging was used for evaluating glomerular filtration rate (GFR, mL/min). Standardized GFR (sGFR), namely GFR/BSA (mL center dot min(-1)center dot m(-2)), was calculated based on the body surface area (BSA). Total sGFR (tsGFR, mL center dot min(-1)center dot m(-2)) was obtained from the sum of sGFR on the left and right sides of all the children. The risk of renal regurgitation was equal in the unilateral reflux group. The sGFR of children with grade IV (45.74 +/- 18.05 mL center dot min(-1)center dot m(-2)) and grade V (49.67 +/- 23.63 mL center dot min(-1)center dot m(-2)) reflux was significantly lower than that in children with grade III (77.69 +/- 22.21 mL center dot min(-1)center dot m(-2)). The renal function compensation of contralateral non-reflux kidney increased in unilateral reflux group, which was higher than that in the control group and level II, IV and V of reflux group respectively. In VUR group of the same grade, sGFR decreased with the age at diagnosis. In unilateral grade V reflux group, the tsGFR was lower than that in the unilateral grade III reflux group (133.51 +/- 48.21 vs. 186.87 +/- 53.49 mL center dot min(-1)center dot m(-2)). The patients with VUR of unilateral grade II were significantly older than those with VUR of unilateral grades III and IV. This study indicates that severe VUR is significantly associated with decreased renal function. Therefore, VUR should be diagnosed early and managed individually.