Objective. To determine the spectrum of serum autoantibodies against endothelial cells and components of the glycocalyx in patients with preeclampsia and to investigate their relationship. Subjects and methods. A prospective case-control study was conducted. The activity of antibody binding to endothelial EA.hy926 cells and the level of peripheral blood anti-hyaluronic acid antibodies were determined in 28 patients with preeclampsia and 30 apparently healthy pregnant women in the third trimester. Results. In preeclampsia, there was an enhanced binding of immunoglobulin G antibodies to endothelial cell antigens, as well as an increased level of immunoglobulin G antibodies against hyaluronic acid [-4GlcAβ1- 3GlcNAcβ1-]n and its repeating disaccharide unit GlcAβ1-3GlcNAcβ. A negative correlation was found between the binding of anti-endothelial cell antibodies and anti-hyaluronic antibodies. Conclusion. The findings may expand knowledge of the pathogenesis of preeclampsia and its practical realization into the diagnosis and prognosis of the disease.