Aims and Objectives: Preeclampsia remains a major cause of maternal mortality and morbbidity. It is a leading indication for iatrogenie premature delivery. Oxidative stress is considered to be one of the factors in the disease process. The present study is centered on the concept that elevated levels of lipid peroxidation (malondialdehyde) due to a decline in the efficacy of antioxidant defenses may predispose an individual to preeclampsia. Material and Methods: In the present study we measured lipid peroxidation products (MDA) and the counteracting enzymatic antioxidants. The study comprises 25 healthy non-pregnant women as controls, 25 third trimester normal pregnant women and 25 preeclamptic patients of the same trimester. Estimation of lipid peroxidation by thiobarbituric acid (TBARS) and enzymatic antioxidants were carried out by standard methods. Results: In the preeclamptic group malondialdehyde, a product of lipid peroxidation, was significantly increased while enzymatic antioxidants like superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase were reduced significantly as compared to normal pregnant and non-pregnant controls. Conclusion: Increased levels of lipid peroxides and reduced antioxidant activities clearly demonstrate the presence of oxidative stress in preeclampsia.