Aim. To estimate the blood levels of primary, secondary, tertiary and unconjugated bile acids in patients with non-alcoholic fatty liver disease.Methods. The study included 74 patients with non-alcoholic fatty liver disease (males - 30, females - 44) and 51 healthy individuals (males - 14, females - 37). All patients underwent anthropometry and complete clinical, biochemical and instrumental examination (measuring the subcutaneous fat layer). 64 patients had hepatic steatosis, 10 - steatohepatitis. Serum levels of bile acids (primary: cholic, chenodeoxycholic; secondary: lithocholic, deoxycholic and tertiary: ursodeoxycholic) were measured by gas-liquid chromatography on «Chromos GC-1000» (Russia) scanner.Results. Unconjugated primary, secondary and tertiary bile acids were detected in the blood of healthy individuals and patients with non-alcoholic fatty liver disease. In healthy individuals, there were no gender differences found in the bile acids levels. Patients with non-alcoholic fatty liver disease had higher level of bile acids compared to healthy controls. There was a significant difference in the concentrations of secondary and tertiary bile acids in patients with hepatic steatosis and steatohepatitis.Conclusion. Blood bile acids levels were significantly higher in patients with non-alcoholic fatty liver disease than in healthy individuals. At steatohepatitis, females had higher levels of cholic, chenodeoxycholic and deoxycholic acids and lower levels of lithocholic and ursodeoxycholic acids compared to males. Significant difference in patients with hepatic steatosis and steatohepatitis was revealed only in levels of secondary and tertiary bile acids.