Growth in children with chronic renal failure caused by polyuric, salt-wasting diseases may be hampered if ongoing sodium and water losses are not corrected. Twenty-four children were treated with polyuric chronic renal insufficiency (CRI; creatinine clearance <65 ml/min per 1.73 m(2)) with low-caloric-density, high-volume, sodium-supplemented feedings. Subsequent growth was compared with that of children in two control groups: a national historic population control from the US Renal Data System database (n = 42), and a literature control (n = 12). Members of the three groups were 81 to 96% white, and 58 to 70% were boys. Obstructive uropathy and dysplasia were the cause of CRI in 92% of the treatment group, 75% of the literature control group, and 30% of the population control group. Treatment effect was assessed in a multivariate, retrospective analysis of the height standard deviation score (SDS), simultaneously controlling for the severity of disease by renal replacement therapy, primary cause of CRI, and initial height SDS. The change in SDS (Delta SDS) for height by regression analysis at 1 yr was significantly greater by +1.37 in the treatment group versus the population control (P = 0.017). The 2-yr height Delta SDS by regression analysis adjusted for creatinine clearance was significantly greater by +1.83 in the treatment group versus the literature control (P = 0.003). Nutritional support with sodium and water supplementation can maintain or improve the growth of children with polyuric, salt-wasting CRI. This inexpensive intervention may delay the need for renal replacement therapy, growth hormone treatment, or both in many of these children and may be used in any clinical setting.