Aim of the study was to investigate the features of the fatty acid (FA) profile of erythrocyte membranes of patients with fatty liver disease (FLD) of mixed genesis (metabolic + alcoholic) from the point of view of atherogenic changes.Material and methods. 31 men (50.6 ± 9.9 years old) with FLD of mixed genesis, the degree of liver fibrosis corresponded to 0-1 (FibroScan ® 502 Echosens, France), and 28 persons of the comparison group, comparable in age, were examined. The study of the composition of FAs of erythrocyte membranes was carried out using gas chromatography/mass spectrometry – a system based on three quadrupoles Agilent 7000B (USA).Results. Patients with FLD of mixed genesis had higher level of palmitoleic (p = 0.03), pentadecanoic (p = 0.05), omega-6 to omega-3 polyunsaturated fatter acids (PUFA) ratio (p = 0.03) and, conversely, lower level of docosahexaenoic (p = 0.0002), total content of eicosapentaenoic and docosahexaenoic FA (p = 0.0007), of all omega-3 PUFA (p = 0.001) in the membranes of erythrocytes compared to healthy persons. There are trends towards a decrease in the content of omega-3 eicosapentaenoic acid and an increase in the ratio of SFA/PUFA in patients with fibroids of mixed genesis in contrast to healthy individuals. The level of individual FA provided high diagnostic accuracy in differentiating patients with FLD of mixed genesis from healthy individuals: palmitoleic (9-C16:1) (area under ROC (AUC) 0.702, sensitivity 66.7 %, specificity 69.6 %), docosahexaenoic (C22:6n-3) (AUC 0.795, sensitivity 77.3 %, specificity 78.3 %), as well as the total content of eicosapentaenoic and docosegexaenoic FA (C20:5n-3 + C22:6n-3) (AUC 0.777, sensitivity 70.1 %, specificity 82.6 %).Conclusions. The revealed features of the profile of erythrocyte membrane FA in FLD of mixed genesis – increase of saturated, monounsaturated, omega-6 PUFA content and reduce of omega-3 PUFA concentration are atherogenic. The continuation of research in terms of the use of FAs as biomarkers of this pathology and targets for therapeutic effects should be considered promising.