The etiology of chronic renal failure (CRF) was studied in 459 Turkish children (205 girls, 254 boys) for the period January 1979-December 1993. Their mean age at onset of CRF was 9.5 +/- 4.2 years (range 1-16 years); CRF was defined as a glomerular filtration rate (GFR) below 50 ml/min per 1.73 m(2) for at least 6 months. When a GFR determination was not available, the serum creatinine concentration was used: greater than 1 mg/dl for children aged 1-3 years, greater than 1.5 mg/dl for those 3-10 years and greater than 2 mg/dl for those 10-16 years. Primary renal disorders were as follows: reflux nephropathy 32.4% glomerular diseases 22.2%, hereditary renal disorders 11.4%, amyloidosis 10.6%, urinary stones 8% and other renal disorders 15.4%. Twenty-three cases of reflux nephropathy (15.4%) were associated with neural tube defects (NTD) and 20 (13.4%) were caused by infravesical obstruction. CRF caused vesicoureteral reflux associated with NTD and amyloidosis are more frequent in our series compared with west European and Nordic countries.