The role of estrogens in the pathophysiology of preeclampsia remains to be determined. The aim of our study was to compare serum concentrations of 17 beta-estradiol and estriol in women with preeclampsia to normotensive pregnant controls. Serum concentrations of estrogens were measured in women with mild (n = 24) and severe (n = 24) preeclampsia as well as is normotensive pregnant controls (n = 24). Patients were matched for gestational age. Pregnancies complicated by early onset severe preeclampsia are associated with increased rates of maternal and fetal morbidity. Subsequently, we created further subgroups before and after 34 weeks of gestation (34 + 0). Serum estrogen concentrations were determined by standard ELISA technique. Compared to normotensive controls, the differences between the overall median serum concentrations of 17 beta-estradiol in women with mild (3811 v. 3730 pg/ml, P = 0.9) and severe (3811 v. 3630 pg/ml, P = 0.1) preeclampsia were statistically not significant. The differences between the overall median serum concentrations of estroil in controls and in patients with mild (121 v. 76 ng/ml, P = 0.6) and severe (121 v. 79 ng/ml, P = 0.4) preeclampsia were similar. The differences between the median concentrations of 17 beta-estradiol in patient with early onset severe preeclampsia compared to patients with mild preeclampsia (3061 v. 3715 pg/ml, P = 0.004) and controls (3061 v. 3807 pg/ml, P = 0.006) were statistically significant. In addition, the differences between the median concentrations of estriol in women with early onset severe preeclampsia compared to controls were statistically significant (20 v. 92 ng/ml, P = 0.02). The differences between the median concentrations of estrogens in those with late onset severe preeclampsia compared to women with mild preeclampsia were not significant. We found significantly lower concentrations of estrogens in women with early onset severe preeclampsia.