The purpose of this study was to evaluate the influence of hepatitis B vaccination on the results of surface antigen tests in blood donors. In this research, eighteen non-immunized volunteers (ten male, eight female) aged 21 to 58 years received 20 ug of the recombinant B vaccine (Heberbiovac-HB) intramuscularly. Blood samples were drawn from all volunteers before the first vaccine dose (day 0) and on days 1,2,3 and 7 after vaccination. HBSAg assessment was done by six different kits (Behring, organon, Diasorin, Equipar, Trinity, Radim ). In this study, seven (39 %) of the eighteen volunteers showed a positive HBSAg reaction, confirmed by the duplicate samples. The most positive reactions were obtained by trinity kit on day 5 and 7. We conclude that individuals recently vaccinated against hepatitis B may have positive tests for HBSAg and it is recommended that such persons defer all blood donations for at least 7 days.