Herpes viruses as CMV, EBV and HHV-6 are the most common cause severe morbidity and mortality in immunocompromised individuals. Reactivation of the virus is seen during periods of down-regulation of the immune system, such as coinfection with other pathogens. So, this study was conducted to detect the presence of Human herpes virus-6 infection in patients with chronic hepatitis C virus (HCV) infection and to point out the effect of HHV 6 -HCV co-infection on Alanine Amino Transferase (ALT) and Aspartate Amino Transferase (AST) liver enzymes. Nested polymerase chain reaction was carried out on extracted DNA from sera of both groups with hepatitis C and control group. Serological investigations were carried out as well. Fifty-three serum samples with HCV-RNA were examined, (25%) were positive HHV-6 DNA, (82%) were positive for HHV-6 IgG antibodies and (22%) were positive for HHV-6 IgM antibodies; among control specimens (18.5%) were positive for HHV-6 DNA infection, (61%) were positive for HHV-6 IgG antibodies and (14.5%) were positive for HHV-6 IgM antibodies. Moreover, the activity levels of ALT and AST liver enzymes were significantly higher in HHV-6 positive patients than that of HHV-6 negative patients. This indicates to the prevalence of HHV-6 infection is common in chronic HCV patients, that increase the severity of liver inflammation.