Despite the high prevalence of and therapeutic attention to growth failure in children with chronic renal failure (CRF), systematic evaluations of spontaneous growth in CRF are lacking. Therefore, we collected retrospectively longitudinal growth and biochemical data in 321 prepubertal patients treated for CRF due to congenital renal disorders. Data were recorded at 3-month intervals during the first 2 years of life and 6-monthly thereafter, up to the age of 10 years. Around 100 measurements were available per age interval. Mixed-longitudinal percentile curves of height and height velocity were constructed. Moreover, a statistical comparison with the heights and height velocities of healthy children and an evaluation of the effect of biochemical parameters on growth was performed. The CRF children had normal heights at birth but dropped below the 3rd normal percentile during the first 15 months of life. Thereafter, growth patterns usually were percentile parallel, with a mean height standard deviation score (SDS) of -2.37 +/- 1.6. Height velocities were consistently lower in patients with glomerular filtration rates (GFRs) below one-third of the lower normal limit (25 ml/min per 1.73 m2 for patients > 1 year) than in patients with better renal function. This difference in growth rates resulted in a mean height SDS of -1.65 +/- 1.5 SDS and -2.79 +/- 1.4 SDS (age 1-10 years) in the subgroups with relatively better and worse GFR, respectively. Regression analysis confirmed that GFR was a weak but significant predictor of height velocity SDS in most age groups.