OBJECTIVE Elevation of urinary levels of interleukin-6 and 8 has been observed in patients with acute urinary tract infections. However, to our knowledge there have been no studies concerning the secretion of interleukin-6 and 8 into the urine after acute inflammation has resolved and renal scarring has occurred. On the other hand, it is well known that cytokines are variously related to glomerular diseases and, thus, it is possible that the progression of reflux nephropathy depends on interleukin-6 or 8. Therefore, we assessed urinary levels of interleukin-6 and 8 in children with vesicoureteral reflux and/or renal scarring. METHODS We evaluated interleukin-6 and interleukin-8 levels in the urine of 32 children without a urinary tract infection who presented or were admitted to our hospital because of vesicoureteral reflux between April and December 1994. Interleukin-6 and 8 were determined using a commercially available human enzyme-linked immunosorbent assay kit and the 2-step sandwich method. RESULTS Urinary interleukin-6 levels were below the lower detection limit (less than 10 pg./ml.) in all samples. There were statistically significant differences between urinary interleukin-8 levels in children with and without renal scarring (p = 0.001), and with and without vesicoureteral reflux (p = 0.0246). CONCLUSIONS Urinary interleukin-8 is an effective marker for renal scarring and vesicoureteral reflux.