Total serum lipids in normal pregnant subjects were significantly higher than those in non-pregnant subjects. This was due to an increase in the lipid content in all of the lipoprotein fractions, especially in VLDL. Serum lipids in pre-eclamptic subjects were higher than those in normal pregnant subjects. This was due to the increase in both VLDL and LDL. Serum lipid peroxide levels in pregnant subjects were significantly higher than those in non-pregnant subjects and further elevation of the levels was observed in pre-eclamptic subjects. The elevation of the peroxide levels in normal pregnant subjects was due to changes in all of the fractions of serum lipoproteins, especially in VLDL. The further elevation of peroxide in pre-eclamptic subjects resulted from an increase in HDL fraction.