This study was carried out to evaluate some immunological and haematological indices of HBV infected subjects in Nnamdi Azikiwe University Teaching Hospital, Nnewi. A total of 150 blood samples were collected from confirmed HBV positive subjects that have tested negative to HIV and HCV and consisted of (65 males) and (85 females) with average age of 35 years. A 102 apparently healthy subjects (controls), consisted of (58 males) and (44 females) with average age of 35 years. The investigations for positive and control subjects were done using standard methods. Haematological parameters were assessed using Sysmex KX-21 N automated counter. CD4 was estimated using Partec CD4 easy count kit with Partec IVD Flow Cytometer. IgG and IgM levels were determined using quantitative turbidmetric method at 540 and 340 nm. Serological markers: HBsAg, HBeAg, HBsAb, HBeAb and HBcAb were determined using one step cassette HBV test kit. Results revealed that there was significant difference between the haemoglobin concentration, monocytes and packed cell volume of hepatitis B infected subjects of different age group (P<0.05). The IgM of the positive subjects was significantly lower than that of the control negative subjects (P<0.05). The IgM of the HbAg positive markers was significantly lower than that of the control negative counterpart likewise the female subjects (P<0.05). The CD4 count, absolute eosinophils count and monocytes count of HbsAg positive subjects were significantly lower than that of the HbAg negative subjects (P<0.05). The absolute eosinophils count of HbAg positive males was significantly lower than that of the control negative subjects (P<0.05). We also discovered that the CD4 count, absolute lymphocyte count and monocytes counts were significantly lower in HbAg positive females than their control counterpart (P<0.05). The haemoglobin concentration, eosinophils count and monocytes count of the HbAg positive subjects was significantly lower than that of the control counterparts. It also revealed high prevalence markers of HBV in the study population as, HBsAg (88%) , HBeAg (30.7%) , HBsAb (4.0%) , HBeAb (8.0%) , HBcAb (13.3%) and high prevalence HBcAb (54.9 %) markers in control negative subjects (P<0.05) . The importance of proper evaluation using all hepatitis B markers for immunological and haematological diagnosis of hepatitis B virus infection cannot be neglected.The result of this study shows the need to include all the serological markers, immunological and haematological parameters in routine diagnosis of HBV infection in Nigeria. It also confirms the fact that testing blood donors for HBsAg alone is not sufficient to eliminate HBV from blood.