Hepatitis C virus (HCV) is responsible for the majority of cases of transfusion-related hepatitis. We performed a first-generation anti-HCV EIA in 665 repeat and 168 first-time blood donors from Berlin. 4.7 and 4.2%, respectively, showed at least one indeterminate or positive result. We further looked for HCV genome in the plasma of 20 donors with reactive anti-HCV-EIA doing a polymerase chain reaction (nested PCR). The control group consisted of 20 patients with chronic hepatitis C. The PCR was negative in all examined blood donors, but was positive in 17 of 20 controls. These findings raise the question, if a positive anti-HCV test correlates with infectiosity.