This review considers the structure and regulation of endothelial activity, its role in angiogenesis and homeostasis maintenance. A special attention is paid to the influence of the vascular wall on the blood coagulation system and to the anti-thrombogenic properties of the endothelium. Different variants of endothelial dysfunction are presented, which can be severe and accompanied by high pro-thrombogenic activity, thrombosis, ischemia and fibrosis of organs and tissues or, conversely, have a slower course, in which the vascular intima involved in the process reduces its anti-thrombogenic function. The influence of these changes on homeostasis and the course of various diseases, including in obstetrics and gynecology, as well as the possibilities of modern diagnostics of endothelial dysfunction are discussed. © 2022, Dynasty Publishing House. All rights reserved.