Umbilical plasma levels of lipoproteins-cholesterol were measured in 480 normal newborns delivered by spontaneous vaginal delivery at 39 to 40 weeks of gestation. Plasma concentrations of lipids were related to fetal weight, abdominal and head circumference, and ponderal index at birth. Plasma concentration of low-density lipoprotein cholesterol (LDL-C) correlated negatively with abdominal circumference (AC), birth weight, and head circumference of newborns (p < 0.021, p < 0.023, p < 0.044, respectively). The baby with the smallest AC had the highest plasma concentration of LDL-C (p < 0.015). In the 165 neonates with ponderal index < 10th percentile, LDL-C was substantially elevated (p < 0.018). These findings suggest that disproportionate size at birth is associated with altered lipid metabolism. These abnormalities, if they persist, might lead to metabolic diseases in adulthood.