Traditional evaluation of renal transplant (Tx) candidates includes a voiding cystourethrogram (VCUG) to assess for vesicoureteral reflux (VUR). The role of pre-Tx VCUG in the work-up of adults has been questioned due to the low yield of positive findings, leading some to recommend screening only pts at high risk for VUR. Since VUR naturally occurs at a higher incidence in children and since children and young adults often have different etiologies for their end stage renal disease (ESRD) than older adults, we reviewed 272 consecutive renal Tx performed in children and young adults between 1980 and 1997 to evaluate the utility of pre-Tx VCUG. Etiology of ESRD included acquired glomerular disease in 25%, dysplasia in 19%, obstructive uropathy in 19%, hereditary renal disease in 16%, other medical renal disease in 8%, other urologic disease in 4%, and unknown cause in 9%. 58% of pts were boys. Mean age at Tx was 13.8 ± 0.5 yrs. There was no difference in mean age at Tx among the various ESRD etiologies. Pre-Tx VCUG was performed in 264/272 pts, of whom 124 had VUR. VUR frequency did not vary by gender. VUR frequency did vary significantly (p=0.0001) by ESRD etiology: obstructive uropathy (86%), other urologic disease (71%), dysplasia (44%), other renal disease (38%), hereditary disease (33%), and acquired glomerular disease (22%). Pts with obstructive uropathy were more likely to have VUR than pts with acquired glomerular disease, dysplasia, hereditary renal disease, or other renal disease (p<0.003). Mean age at Tx of pts with VUR was lower than mean age at Tx of pts without VUR (12.2 ± 0.7 vs. 15.2 ± 0.6 yrs; p=0.002). Since VUR often spontaneously resolves by mid-childhood, we stratified pts by age at Tx: <7 yrs (n=62), 8-15 yrs (n=135), and >16 yrs (n=67). VUR frequency differed significantly by age with 71% of children<7 yrs at Tx having VUR, compared to 49% of 8-15 yrs, and 38% of pts >16 yrs (p=0.002). When stratified by both age and ESRD etiology, the tendency for younger pts to have more frequent VUR persisted only for acquired glomerular disease (p=0.002). Of the 124 pts with VUR, 102 (82%) underwent pre-Tx nephrectomy or other surgical repair. We conclude that: 1) In contrast to older adult renal Tx pts, VUR is commonly detected pre-Tx in children and young adults; 2) Although its frequency varies by ESRD etiology, VUR is prevalent in both urologic and medical renal disease; 3) VUR is not age dependent in most causes of ESRD in young pts; 4) Most young pts with VUR undergo pre-Tx surgery. We believe these results strongly support pre-Tx VCUG in pediatric ESRD.