The authors compared the concentrations of conjugated diens (CD), lipid hydroperoxides (HEPTE) and malonyl dialdehyde (MDA), in blood serum and placental tissue of 15 parturients with pregnancy induced hypertension (PIH) and 15 normotensive controls matched for gestational age. The CD and HEPTE were measured according to the Ward method, and the MDA level was quantified by means of the Ledwozyw method. In the placental homogenates of women with gestosis, levels of lipoperoxidation products were not significantly changed in comparison to the control group. In patients with PIH, the blood serum concentrations of CD, HEPTE and MDA exceeded the control values by 48.28%, 169.47% and 57.59%, respectively (p < 0.001). Lipid peroxidation seems to play an important role in pathogenesis of the pregnancy associated hypertensive disorders.