Plasma lipids were determined in the cord blood of 19 term, 16 preterm and 14 light-for-dates babies. Plasma triglyceride concentration was higher in the term than in the preterm group and was highest in the light-for-dates group. The proportions of poly unsaturated fatty acids in triglyceride and in cholesterol ester were higher in term than in preterm babies; values for light-for-dates babies did not differ from term babies. Plasma triglyceride concentrations were affected by the maturity of the pregnancy and also by the nutritional status of the fetus. The levels of polyunsaturated fatty acids were also related to the maturity of the pregnancy but were independent of the nutritional status of the fetus.