Background: Haemotological abnormalities were common in patients with HIV infection. The common peripheral blood findings include anemia, thrombocytopenia, leucopenia or pancytopenia. These abnormalities may be attributable to the direct toxic effect of the virus on progenitor cells, ineffective hematopoiesis, opportunistic infections, immune mechanisms and drug reactions. Methods: It was a hospital based observational descriptive study conducted in department of medicine and ART centre at S P medical College Bikaner and associated group of hospital. Results: Leucopenia was seen in 46% cases and thrombocytopenia in 13% of cases. Hemoglobin level below 10gm% was seen in 65%. Mean HB level in HIV patients was 8.32±2.64/dl, total WBC level was 4.27±0.54×103 cells/μl, Absolute lymphocytes level was 0.059±0.023×103 cells/μl and platelet level was 13.29±6.76×103 cells/μL. Conclusion: Hematological abnormalities were common in patients with Acquired Immuno Deficiency Syndrome. Hemoglobin concentration, percentage of neutrophils and lymphocytes were significantly reduced.