The accumulation of sudanophilic material in and around small telencephalic vessels was studied in 215 randomly collected brains of infants and children up to 8 years in relation to age and the primary lethal disease process. Before the fourth postnatal week lipid deposits occur in the premyelination glia and in endothelial and perithelial cells. After this age, lipid droplets and lipid-laden macrophages are present in variable amounts around small veins and arterioles, predominantly in the subcortical white matter and deep cerebral cortex and, occasionally, in the internal capsule and around subependymal veins. The highest amounts are present between the age of 3 and 6 months during the gradual disappearance of the lipid-laden premyelination glia, and then constantly decrease up to the age of 3 years. The occurrence and intensity of perivascular lipid deposits are apparently independent of cerebral oedema and without relation to any primary lethal disease. These lipid aggregates contain unsaturated triglycerides, cholesterol esters and phospholipids, whereas there is no evidence of sulphatides and cerebrosides, They are considered to be physiological findings and are attributed to the export of residual and excess lipid material not used in the formation of myelin.