A study carried out on 2,006 Tunisian blood donors permitted us to evaluate the prevalence of hepatitis C virus antibodies (anti-HCV) which was 1.09%; frequency of indirect markers of NANBH were as follows: ALAT greater than 2 N (1.24%), anti-HBc (30.35%), 55.5% of HCV (+) donors had anti-HBc (+), 12.5% had rises ALAT and only 33.3% both markers.