Basic research during the past two decades has led to increased awareness of the role of lipid peroxidation in various physiologic and pathophysiologic processes. A number of reports indicate that preeclampsia is associated with elevated blood levels of lipid peroxidation products. In view of its potentially destructive character, uncontrolled lipid peroxidation has been suggested as an etiologic factor in preeclampsia. The present article summarizes current information regarding the occurrence of lipid peroxidation in normal and preeclamptic pregnancy. Recent progress concerning our understanding of the process of lipid peroxidation and its role in cardiovascular disease is also reviewed. This information is used to discuss potential mechanisms by which lipid peroxidation might contribute to the pathogenesis of preeclampsia.