The aim: To establish the dependence of the concentration of galectin-9(CGal-9) in the serum of patients with chronic viral hepatitis C (CVHC) on the type of antiviral therapy (AVT), clinical-laboratory, autoimmune and integrative parameters, non-invasive methods of assessing the degree of fibrosis. Materials and methods: CGal-9 in serum were determined in 68 patients with CVHC and 20 healthy individuals, and clinical-laboratory and integrative parameters, noninvasive methods for assessing the degree of fibrosis were studied. Results:There were three groups: baseline (I), pegylated interferon (PEG-IFN) with ribavirin (II), velpatasvir with sofosbuvir (III). In pations from group I, compared with healthy people, CGal-9 was 1.7 times higher (p <0.05); in patients from group II it was 4.2 times higher (p<0.05); in patients from group III it did not differ from healthy individuals. All patients had a directly proportional correlation between CGal-9 and the frequency of splenomegaly detection; in patients who did not receive AVT, directly proportional – with De Ritis ratio, non-invasive methods of liver fibrosis, inversely proportional – with platelet count (p<0,05). There was a higher probability of positive indicators of antinuclear antibodies (ANA) at 12 weeks of treatment with PEG-IFN and ribavirin, with higher CGal-9 at 4 weeks of AVT (p<0,05). Conclusions: Correlations between CGal-9 and the frequency of splenomegaly detection, platelet count, De Ritis ratio, degree of lever fibrosis in correlation with METAVIR, APRI, FIB-4, ANA, NI were determined. The possibility of predicting the occurrence of splenomegaly, liver cirrhosis and positive ANA in patients with CVHC has been proven.