Neonatal hypoglycaemia is the commonest clinical manifestation af disordered energy metabolism and is important because sustained hypoglycaemia may cause neuronal damage. Infants at high risk of developing low brain energy levels are those who have increased metabolic demands, low glycogen reserves, insufficient counter-regulatory responses or hyperinsuliaemia, and there is accumulating evidence that blood glucose should be maintained above 2.5 mM in this group. If possible, early and regular feeding at a volume of 120 ml/kg/dag should be established, but supplementation with intravenous glucose may be necessary.