The growth pattern and dietary intake of 33 children with varying degrees of renal insufficiency has been investigated. The development of impaired renal function in infancy has a more deleterious effect on linear growth than has its onset in later years. A reduction in growth velocity may occur once the glomerular filtration rate falls below 25 ml/min/1.73m(2). There was a significant reduction of the energy, protein, and vitamin D intakes of children with renal insufficiency compared with those recommended for their age, and of energy intake compared with that of normal children of their own height. Reduced growth velocity occurred when energy intake fell below 80% of that recommended. The reduction in the intake of energy and nutrients in these children may in part be responsible for their growth retardation.