Fasting plasma concentrations of triglycerides (TG), cholesterol, immunoreactive insulin (IRI), and blood glucose were raised in 16 children with chronic renal failure on regular haemodialysis compared with 18 healthy children. In the patients plasma IRI correlated positively with plasma TG, while blood glucose did not correlate with IRI or lipid concentrations. Dietary intake, expressed as percentage of recommended intake for height-age, did not correlate with plasma lipids, but there was a positive correlation between plasma TG and the proportion of calories derived from carbohydrate. The children were not malnourished as evidenced by normal plasma albumin and transferrin concentrations. The mechanism of the hyperlipidaemia is unclear but it may be related to the glucose intolerance with hyperinsulinaemia which is found in uraemia. In view of the risk of premature atherosclerosis, plasma lipid concentrations should be monitored in children with chronic renal failure and attempts made to ameliorate hyperlipidaemia with appropriate dietary manipulations.