Plasma antibody against GBV-C (anti-GBV-C) and GBV-C RNA were detected with enzyme immunoassay (EIA) and reverse transcription nested polymerase chain reaction (RT-nPCR) in blood donors to study the prevalence of GBV-C infection in blood donors. Positivity of anti-GBV-C was 4.92 percent in 1,200 plasma donors (59/1,200), and that of GBV-C RNA was 64.41 percent in those with positive anti-GBV-C (38/59). Positivity of anti-GBV-C was 2.86 percent in 350 whole blood donors (10/350) and that of GBV-C RNA was 60.00 percent in those with positive anti-GBV-C (6/10). Positive rate of anti-GBV-C in those who donated blood for more than 10 years was higher than in control group. It suggests that infection with GBV-C was more often in plasma and blood donors. There were blood donors with positive GBV-C RNA but normal ALT activities and those both positive in GBV-C RNA and HCV RNA. It is urgent to detect the markers of GBV-C infection in blood donors as soon as possible.