Objective. To study the development of PlGF and sFlt-1 reference intervals and their ratios as well as to assess its production in preeclampsia of different severity. Material and methods. The study included 374 women with normal pregnancy (11—40th gestational weeks) and 148 patients with preeclampsia of dufferent severity (20—40th gestational weeks). The comparison group consisted of 14 pregnant women with arterial hypertension developed at 37—40th gestational weeks. The concentration of PlGF and sFlt-1 was measured with help of automatic electrochemiluminescence analyzer Cobas e411 («Hitachi», Japan). Results. The obtained results allowed to establish the reference intervals of PlGF and sFlt-1 concentrations and their ratio in the dynamics I (11 weeks, II and III trimesters of pregnancy). It is shown that women with preeclampsia has increased sFlt-1concentration, increased sFlt/PlGF ratio and decreased PlGF concentrations. The identified features are the most expressed for severe pre-eclampsia. Conclusion. Studied markers of pre-eclampsia can be used in clinical practice for taking decision about pregnancy prolongation.