The present study included a total of 46 patients presenting with chronic viral hepatitis C treated with pegilated interferon. The objective of the work was to elucidate the relationship between anemia as a complication of therapy of chronic hepatitis C and the individual characteristics of the patients in the course of the disease. Anemia and erythropenia were diagnosed in 75% and 46% of the patients given antiviral treatment respectively. The reduction in the hemoglobin level and the number of erythrocytes in blood was believed to be a consequence of therapy because these changes coincided with the onset of the treatment. Moreover, both parameters returned to the respective initial values after the discontinuation of therapy. The development of anemia and erythropenia was shown to depend on gender: these conditions were more frequently diagnosed in women than in men. The severity of anemia was directly dependent on the level of viremia, probably because of the strong viral load on the organism exhausted its compensatory reserves.