Reflux nephropathy is a progressive renal scarring due to chronic pyelonephritis developing in patients with vesico-ureteral reflux. TGF-beta1 is thought to be one of the most important factor that initiates reflux nephropathy and stimulates its progression. The purpose of the study was to assess serum TGF-beta1 level in children with reflux nephropathy. The study comprised 36 children (12 boys and 24 girls) aged 1-17 years with vesicoureteral reflux and renal scarring confirmed by scintigraphic evaluation. In most children recurrent urinary tract infections were observed. In 13 (27.8%) children, a first episode of urinary tract infection occurred in infancy. Primary vesico-ureteral reflux was diagnosed in 18 (50.0%) children. Secondary vesico-ureteral reflux due to anatomic or functional subvesical obstruction were recognized in 11 (30.6%) and 7 (19.4%) children, respectively. Serum TGF-beta1 levels were measured by ELISA. The mean serum TGF-beta1 level in children with reflux nephropathy was significantly lower than that in controls (92.04 +/- 33.14 ng/ml vs 141.73 +/- 45.38 ng/ml). This might be a result of increased influx of serum TGF-beta1 into renal parenchyma and/or increased urinary TGF-beta1 excretion due to tubular damage in children with reflux nephropathy.