Objective: Abnormal trophoblastic invasion and impaired placentation have a crucial role in the etiopathogenesis of preeclampsia (PrE). Trophoblastic cells are involved in invading the maternal decidua and remodelling of the spiral arteries with matrix metalloproteinase-14 (MMP14). MMP-14 cleavage of endoglin releases its extracellular region, the soluble form of endoglin (s-ENG), into the maternal circulation. In PrE, there is a relationship between endothelial dysfunction and s-ENG concentration. The aim was to determine and compare the serum levels of s-ENG and MMP-14 in different groups of PrE patients and healthy subjects.Material and Methods: The study included 30 patients with late-onset preeclampsia (L-PrE) (group 1; gestational age ≥34 weeks), 33 patients with normal pregnancy (group 2; gestational age ≥34 weeks), 31 patients early-onset preeclampsia (E-PrE) (group 3; gestational age <34 weeks), and 31 patients with normal pregnancy (group 4; gestational age <34 weeks). s-ENG and MMP-14 concentrations measured using enzyme-linked immunosorbent assays were compared.Results: In all groups, MMP-14 concentrations decreased with increasing gestational age. s-ENG concentrations were highest in the E-PrE group. In groups 1 and 3, 29 had mild PrE while 32 suffered severe PrE and s-ENG concentrations did not differ between mild and severe preeclampsia (p=0.133). However, there was a significant difference in MMP-14 concentration comparing mild with severe PrE (3.11±0.61 vs 3.54±1.00; p=0.047, respectively). There was no correlation between s-ENG and MMP-14 concentrations. Conclusion: MMP-14 and s-ENG concentrations can be predictive biomarkers for the diagnosis of PrE. Maternal serum MMP-14 concentration may be a biomarker for determining the severity of PrE. (J Turk Ger Gynecol Assoc 2021; 22: 29-36)