GB virus C/hepatitis G virus (GBV-C/HGV) is a recently discovered Flavivirus, considered to be a cause of hepatitis. The purpose of this study was to determine the prevalence of HGV in blood donors in Isparta, a Mediterranean city of Turkey. The prevalence of HGV-RNA and antibodies to the envelope 2 antigen (anti-E2), a marker of past infection, in blood donors were investigated. The study group consisted of 60 blood donors in the April 2001–July 2001 period. Serum samples were tested for the presence of HGV-RNA by real time polymerase chain reaction (PCR) and for anti-E2 by a commercial enzyme-linked immunosorbent assay (ELISA). GBV-C/HGV RNA was present in the sera from 1.66% of the blood donors, and anti-HGV E2 antibodies could be detected in 6.66% of the samples. In conclusion, the percentage of previous or current infection (viremia and/or antibody to E2) was detected as 8.33% in blood donors, indicating that GBV-C/HGV infection appears to be common among blood donors in the region even in the absence of blood transfusion. Thus, the results support that HGV is transmissible not only by blood transfusion, but probably also by other transmission routes such as sexual and intrafamilial contact.