Incidence of chronic renal failure in children is not yet clearly known. In recent years it has been evaluated on the basis of the number of patients accepted into dialysis-transplantation programs and is thus underestimated, as registries do not list children who are not treated for technical reasons, lack of facilities or health policy. The number of new patients per year per million child population varies widely. Differences among countries are mainly related to economic development. In developed countries the incidence of CRF remains stable or decreases slowly owing to early diagnosis, improved conservative treatment, prevention of genetically-transmitted diseases, whereas the prevalence increases steadily as a consequence of improved replacement therapy. Causes of primary renal diseases have been analyzed in several series totaling over 9400 children. The most frequent cause is chronic primary glomerulonephritis followed by pyelonephritis, including obstructive uropathies and vesico-ureteral reflux. Differences in geographical distribution of etiologies are also analyzed. The relative contribution of chronic peritoneal dialysis and hemodialysis in the treatment of children with ESRF varies from country to country. Several problems regarding CRF in children are briefly discussed: prevention of renal failure, extension of treatment opportunities to more children, quality of replacement therapy, and clinical rehabilitation of children.