Background. The investigation of violation of the functional state of the endothelium and morphofunctional properties of erythrocytes in non-alcoholic steatohepatitis (NASH) combined with chronic obstructive pulmonary disease (COPD) in patients with obesity was the purpose of our study. Materials and methods. We have examined 30 patients with NASH on the background of degree I obesity (group 1), 30 patients with COPD and normal body weight (group 2), 60 patients with NASH in combination with COPD (group 3) and 20 apparently healthy persons. The functional state of the endothelium was studied by the content of stable metabolites of nitrogen monoxide (nitrites/nitrates), endothelin-1 (ET-1), and the number of circulating excised endothelial cells (CEEC) with soluble vascular cell adhesion molecule-1 (sVCAM-1) content in the blood. The erythrocyte deformity index (EDI), the relative viscosity of the erythrocytic suspension (RVES) and the percentage of peroxide hemolysis of erythrocytes (PHE) were also determined. Results. The conducted study showed that the course of NASH in its combination with COPD in patients with degree I obesity is accompanied by an increase in the level of ET-1 (by 5.8 times), sVCAM-1 (5.6-fold), CEEC (2.1-fold), RVES (by 65 %) and the percentage of PHE (2.1-fold) while simultaneously reducing the content of stable metabolites of nitrogen monoxide (nitrites/nitrates) (2.1-fold) and EDI (by 36.2 %) compared to those in apparently healthy subjects. Conclusions. With a combined course of NASH and COPD in patients with degree I obesity, endothelial dysfunction develops, which is characterized by elevated levels of ET-1, sVCAM in the blood serum and CEEC, with the maximum decrease in the content of nitrites/nitrates in the blood. One of the factors leading to the aggravation of microcirculatory disorders in NASH combined with COPD is the changes in the morphofunctional state of erythrocytes (reduction of the EDI with simultaneous increase in RVES and percentage of PHE).