Preeclampsia is a common serious disorder of human pregnancy, which is associated with significant maternal and perinatal morbidity and mortality. The suspected aetiology of preeclampsia is complex, therefore there are no reliable predictors of early preeclampsia onset. For this reason searching for prognostic pathophysiological markers of preeclampsia development is needed. In view of this, factors of endothelial dysfunction — plasma homocystein and coenzymes, folic acid, vitamins of B group were studied. This study found that homocystein and homocystein/folate ratio may have significant diagnostic value and thus, can be used as prognostic marker in preeclamptic patients OR 8,4 (3.3; 21.43; 95% CI).