Endothelium forms an inner layer of vascular wall. It plays an important role in inflammatory process, regulation of vascular tone, and synthesis of thromboregulatory substances. Leukocyte and endothelium interactions during inflammation are regulated by different families of adhesion molecules. Increased levels of soluble forms of adhesion molecules have been detected in the circulating blood in conditions such as autoimmune diseases, transplant rejection, ischemia-reperfusion injury in addition to neutrophil- and endothelial membrane-bound forms reflecting the level of endothelial dysfunction. It is known that endothelial dysfunction is a risk factor for ischemic events such as stroke, myocardial infarction, unstable angina pectoris, ventricle fibrillation, necessity of revascularisation procedures, and death from cardiovascular reasons. Clinical studies showed that cardiac surgery has an impact on vascular endothelial function as well. The amount of endothelium-derived soluble forms of vascular-1 and intercellular-1 adhesion molecules increases after cardiopulmonary bypass suggesting endothelial dysfunction. However, further investigations are needed to be done to support the evidence that endothelial dysfunction proceeding heart surgery is one of the reasons of tissue ischemia-reperfusion injury.