In a retrospective study covering the years 1974 to 1977 the prevalence of non-terminal renal failure in Swedish children on to 15 years of age was registered as 4.50 per million total population. The mean yearly incidence of terminal renal failure during the same period was registered as 0.94 per million total population. Nephronophthisis was the most common single cause of renal failure. No case of coarse renal scarring due to recurrent urinary tract infections was reported. The Swedish study shows a good agreement with an earlier Swiss one concerning the diseases causing chronic renal failure in children. The frequency of chronic renal failure is expected to be essentially unchanged until breakthroughs occur in research on glomerulonephritis.