Introduction:The infection with the Hepatitis B Virus (HBV) is a global health problem which affects 2 billion people worldwide. In India, the prevalence of the Hepatitis B infection is 4% in the general population. The prevalence of the HBV infection in voluntary blood donors is 1-3%. It has been reported that the viraemia continues even after the clinical recovery from the acute HBV infection. Some blood donors who were negative for the surface antigen but positive for the core antibody have been reported to transmit HBV, leading to acute hepatitis. This study was done to determine the seroprevalence of the hepatitis B core antibody in voluntary blood donors in Chennai, India. Conclusion:If a routine screening of the sera for the core antibody is not done, the low-level HBV viraemia may not be identified. The absence of the surface antigen in the blood of apparently healthy individuals may not be sufficient to ensure the lack of the circulating virus.MahesWari K s, arun r , aruMugaM P