Background: Hepatitis B virus infection is a major global health problem and of immense clinical importance. Hepatitis B virus infection can lead to hepatocellular carcinoma (HCC) and is found to be associated with macrocytic anemia. The mechanism of anaemia largely depends on red cell membrane integrity. Osmotic fragility (OF) of red cells was therefore evaluated in patients with HBV infections to access the diagnostic/prognostic utility. Methods: A total of 1744 patients from surgical and medical wards/clinics of Alex Ekwueme University Teaching Hospital Abakiliki were screening serologically for HBV using immunochromatographic strip method and positive samples were confirmed by the use of One Step Hepatitis B Multi-5 Test. A total of 100 subjects (50 HBV positive and 50 HBV negative) were evaluated for osmotic fragility of red blood cells. Results: HBV prevalence rate of 3.5% was found among the patients. The osmotic fragility of red blood cells were significantly (p<0.05) decreased in Hepatitis B virus positive individuals compared to Hepatitis B virus negative individuals. Significant (p<0.05) differences were observed in the osmotic fragility of the two groups at 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2% and 0.1% saline. The mean corpuscular fragility (MCF) which is the sodium chloride concentration causing 50% hemolysis for Hepatitis B positive individuals was 0.33% saline while that of Hepatitis B negative individuals was 0.41% saline. Conclusion: The HBV positive patients showed decreased OF compared with HBV negative control population. This study was on small population of HBV positive subjects without disease staging. Further studies using more sample size and clinical staging is recommended to clearly associate OF as a diagnostic or prognostic marker in HBV infection