Objective. To study the content of circulating endothelial cells in the blood of patients with alcohol withdrawal syndrome (uncomplicated and complicated delirium). Material and methods. Thirty patients, aged from 18 to 40 years, with the diagnosis of «alcohol withdrawal, uncomplicated» (F10.302) or «alcohol withdrawal complicated by delirium» (F10.40) were examined in the acute state and after 2 weeks of therapy. The control group consisted of 22 normals. The content of circulating endothelial cells (CEC) in the blood was measured by flow-cytometry. Results and conclusion. Significant changes in the CEC content were observed in alcohol withdrawal syndrome: a multiple increase in the number of CECs due to the CEC-Living subpopulation, the appearance of CEC-Dead, which characterized the pronounced damage to the endothelium; the compensatory growth of ECP (CD146+CD34+) and AEC (CD146+CD105+). Patients with uncomplicated abstinence after 2 weeks of therapy showed positive changes in the form of a decrease in CEC level due to the CEC-Living. The CEC level remained high in patients with alcohol delirium after 2 weeks of treatment, the decrease in the content CEC-Living with a significant growth CEC-Dead and a slight compensatory increase in ECP (CD146+CD34+) was observed.