Authors investigated the presence of antibody to hepatitis C virus (anti-HCV) at 67,534 blood donations, and alanin-amino-transferase (ALT) levels were analysed at the same time. The prevalence of anti-HCV antibody was 0.73% at 15,864 blood donors. Frequency of positive reactions of anti-HCV antibody increased paralelly with advance of age. Increased or high serum ALT level was found at more than 50% of samples with positive HCV reactivity. At the base of follow-up the blood donors were screened out from blood donation temporarily or definitively. Anti-HCV donors were taken to hepatic care. The treatment with interferon of HCV seropositive donors proved by PCR (polimerase chain reaction) was started. Transfusion and tattou are underlined as risk factors of HCV infection. The data were analysed according to sex and ages.