Hepatitis C virus (HCV) is an RNA virus of the family Flaviviridae (genus Hepacivirus) which causes acute and chronic liver diseases including chronic hepatitis, cirrhosis and hepatocellular carcinoma. Semaphorins represent a very divergent group of secretory and transmembrane proteins that take part in many important physiological processes such as neural development, angiogenesis, immune response regulation, cancer development etc. The aim of this study was to determine semaphorin-4D, -6D, -3C and -7A concentrations in sera of chronic hepatitis C patients and compare them with chronic hepatitis B patients and healthy controls. Possible correlations between semaphorin concentrations and viral replication kinetics, level of fibrosis or HCV genotype were also analysed. HCV RNA in the serum was quantified using quantitative real-time PCR assay, HCV genotyping was performed by PCR and nucleic acid hybridization whereas semaphorin concentrations in the serum were determined by enzyme immunoassay. Concentrations of semaphorin-7A were significantly increased in patients with chronic hepatitis B and C compared to controls. Concentrations of semaphorin-4D and semaphorin-6D correlated significantly with HCV RNA viremia. Additionally, significant correlation between viremia and fibrosis levels was observed in patients with chronic hepatitis C. No significant differences in semaphorin-3C expression or clinical parameter values in regard to HCV genotype were observed. The results of this study suggest an important role of semaphorins in pathogenesis of chronic viral hepatitis.