HIV infection is associated with various and wide range of haematological abnormalities. Anemia,Leucopenia,Thrombocytopenia are the most commonest haematological abnormalities identified in HIV infected patients.This study was done to observe the haematological abnormalities and correlation of CD 4 cell count in HIV/AIDS infected patients.This study was done as prospective study in government villupuram medical college in 250 cases with HIV infection.Required haematological parameters and CD4 cell count were studied in all 250 cases.The most common haematological abnormality observed in this study was Anemia.The prevalence of Anemia,Leucopenia,Thrombocytopenia were 84%,47%,27% respectively in patients having low CD4 cell count.