The association of vesicoureteral reflux, urinary tract infection and renal parenchymal damage is well known. Recently, it was reported that the angiotensin converting enzyme (ACE) DD gene polymorphism is a risk factor for renal damage in patients with congenital uropathies and high grade vesicoureteral reflux. We determine risk factors associated with renal damage in patients with primary familial vesicoureteral reflux. We reviewed the medical and radiological records of 188 siblings with primary vesicoureteral reflux comprising 88 families. We excluded from study 26 patients because of insufficient clinical information. Mean age at diagnosis of the remaining 92 girls and 70 boys was 2.3 years. Reflux was diagnosed by voiding cystourethrography and dimercapto-succinic acid scan was performed to evaluate renal scarring. The ACE I/D polymorphism was detected by polymerase chain reaction. For multivariate analysis risk factors, such as gender, age at diagnosis, history of urinary tract infection, reflux grade and ACE genotype, were analyzed in logistic regression model. Renal parenchymal damage was detected in 45 (28%) of the 162 siblings. Multivariate analysis revealed that reflux grade (p <0.0001), history of urinary tract infection (p = 0.010) and age at diagnosis (p = 0.044) were the most significant independent risk factors for renal parenchymal damage. Angiotensin converting enzyme genotype and gender were not significant. In univariate analysis ACE DD genotype significantly linked to grades IV and V reflux (p = 0.007) rather than renal parenchymal damage (p = 0.284). In primary familial vesicoureteral reflux, history of urinary tract infection, reflux grade, and age at diagnosis are the most important risk factors for renal parenchymal damage. ACE DD genotype is not associated with renal damage in familial vesicoureteral reflux.