During the period from 1994 – 1997 the authors examined for the presence of HBsAg and anti-HCV antibodies 828 320 times all blood donors. During repeated examinations HBsAg was found in 660 donors (0.0798 %) and anti-HCV antibodies in 380 instances (0.0458 %). The prevalence of positivity of both investigated "markers" of hepatitis gradually declines and the lowest values are in 1997. From the presented results ensues the necessity of strict monitoring for the presence of "markers" of hepatitis and other infectious diseases in blood donors as thus possible transmission by trans- fusion of blood or its derivatives can be eliminated in a significant way.

        Key words: post-transfusion hepatitis – hepatitis B – hepatitis C