Context. Despite the fact that preeclampsia (PE) is a leading cause of perinatal morbidity and mortality, the pathophysiology of PE remains unknown. Early prediction of this disease may allow for timely initiation of preventive therapy. Patients. To evaluate the predictors of PE by investigating serum biomarker in the first trimester we prospectively recruited 645 women that underwent an 11-13 weeks aneuploidy screening. Among them 25 (3.86%) were diagnosed with PE. These women were included in the first group. All women of the first group had mild PE with late onset. The control group (II group) includes 63 patients without PE by random sampling from rest 620 women. Methods. Blood samples were drawn at 11-13 weeks of gestation. Serum levels of PAPP-A, cystatin C, retinol binding protein 4 (RBP), a disintegrin and metalloprotease (ADAM12) was measured using an automated immunoassay analyzer (DELFIA System, Finland), BioVendor, Chech Republic, AssayPro, Cloud-Clone Corporation (USA). Analyses were computed using Statistica 12.5 and MedCalc 15.8, MS EXCEL 2010. Results. Level of PAPP-A was 1.92 ME/ml (0.80; 2.82) in first group 2.26 (1.14; 3.84) and in control group (p=0.269), ADAM12 was 1.79 ng/ml (0.93; 2.30) in I group and 0.84 (0.48; 1.29) in II group (p=0.0001), cystatin C was 524.26 ng/ml (425.44; 576.33) in I group, 535.50 (484.62; 626.04) in control group (p=0.160), RBP4 was 44.36 mkg/ml (34.95; 48.52) in I group and 32.53 (25.81; 36.29) in control group (p=0.0003). We used logistic regression for forecasting of PE (p=0.001) and ROC analysis for receiving a point of division with indicators of Se and Sp optimum for this case. Yuden's index gives us cutoff and regression – the equation: cutoff for ADAM12 was 1.35 ng/ml (Se=78%, Sp=68%), for RBP4 70.2 mkg/ml (Se=70%, Sp=72%) for prognosis of preeclampsia. Using decision tree, we came to conclusion that: we could expect PE if RBP4>87.90 mkg/ml. If RBP4 ≤87.90 mkg/ml, we should use ADAM12: if it> 2.33 ng/ml, we also could expect late-onset PE (Se=87.5 % and Sp=85%, OR=39.667 (3.498; 49.83)). Conclusion. So, all used markers could be early predictable factors for PE. But to prove our results it is necessary to make more investigations using these biomarkers.