The aim of the study is to investigate the plasma and placental levels of malondialdehyde, glutathione and superoxide dismutase in normotensive and pre-eclamptic pregnancies. Peripheral venous blood samples were collected before labour (35.3 ± 1.1 and 34.2 ± 3.4 weeks for normotensive and pre-eclamptic, respectively) and placental tissues was obtained after delivery from 34 pre-eclampsia and 33 normotensive pregnancies. The mean plasma and placental levels of malondialdehyde were significantly higher, glutathione and superoxide dismutase levels were significantly lower in pre-eclamptic compared with normotensive patients (P < 0.01). The plasma and placental levels of malondialdehyde significantly increased, glutathione and superoxide dismutase significantly decreased with the increments in diastolic blood pressure. As a conclusion maternal circulating and placental tissue levels of lipid peroxides increase whereas antioxidants decrease in pre-eclampsia. The magnitude of oxidative stress and antioxidant changes correlate well with diastolic blood pressure.