Background: Post Transfusion hepatitis B viral infection is a major problem even after adoption of mandatory screening test, HBsAg by ELISA test in blood banks. In Egypt, HBsAg is the only HBV screening test of blood donors in most bloods banks. However HBsAg negative blood donors does not rule out the risk of transmission of hepatitis B, as the donor may be in the 'window period' or has a mutant strain. During this period, detection of the antibody to the hepatitis B core antigen (anti-HBc) IgM type is a useful serological marker. Objective: this study aimed to evaluate the significance of screening anti-HBc IgM for HBsAg negative blood donors to reduce the risk of transfusion transmitted HBV infection in Egypt. Methodology: Four hundred HBsAg negative blood donors were randomly selected from Al-Zahraa University hospital blood bank, for further screening by anti-HBcIgM by ELISA test, then positive samples for anti-HBcIgM were tested for HBV DNA by PCR. Results: Nine (2.25%) out of selected 400 samples were positive for anti-HBcIgM, and 4 (1%) out of these 9 samples Conclusion: Anti HBcAg IgM screening test should be implemented as an additional screening test for blood donors in Egypt, to improve transfusion safety as it is an indicator of occult HBV during window period.