The group of infectious agents causing viral hepatitis was extended by another virus the detection of which was published in 1995. This virus is described as virus of hepatitis G (HGV) or GBV-C virus and is included among RNA viruses family Flaviviridae. Detection of HGV is based on reverse transcription with subsequent amplification of the viral nucleic acid by means of a polymerase chain reaction. The authors examined sera of 82 chronically haemodialyzed patients incl. 22 (26.8%) HGV RNA positive ones, whereby coinfection with HBV was proved in 3 specimens (13%). In 6 HGV RNA positive samples anti-HCV positivity was found (27%), incl. one sample where HCV RNA positivity was proved (4.5%). Raised transaminase activity was found only in three patients with HGV RNA positivity (13.6%). From the presented results ensues that haemodialyzed patients are a high risk group for HGV infection.