PURPOSE: We analyzed the demographic data and clinical course of Korean children with chronic renal failure (CRF) observed between 1990 and 1999. PATIENTS AND METHODS: Questionnaires were mailed to all children's hospitals all through the country. We asked for primary renal disease, age and serum creatinine levels at first presentation with CRF and end-stage renal disease (ESRD), and modes of renal replacement therapy (RRT). RESULTS: 401 children (254 boys, 147 girls) with CRF, defined as a permanent increase of serum creatinine above 1.2 mg/dl for at least 3 months or until death, were identified. This represents an incidence of 3.68 per million child population per year. Of these patients, 22% were younger than 5 years, 28% 5 to 10 years and 50% 10 to 15 years. Eight five % of the patients could be classified with a primary renal disease. The most frequent cause is glomerulonephritis (36%), followed by chronic pyelonephritis (21%), renal hypo/dysplasia (9%), and hereditary nephropathies (7%). Reflux nephropathy (16%) was the most common single cause of CRF. ESRD was reached in 70% of all patient: 99.3% of these started RRT. Hemodialysis (HD, 42%), peritoneal dialysis (PD, 35%) and transplantation (TP, 23%) were performed as the initial mode of RRT. A total of 161 TPs were performed (159 first grafts, 2 second grafts). A total of 32 patients died. The main causes of death were dialysis related complication in HD patients and infections in PD patients. Survival rate on any form of RRT was 88.7% during the mean follow-up period of 37 months. CONCLUSION: Major efforts should be directed toward earlier diagnosis and treatment of reflux nephropathy to prevent occurrence of CRF. Dialysis and TP have now become well accepted forms of treatment in Korean children with ESRD.