Background: Tuberculosis is a chronic granulomatous inflammation highly prevalent in developing countries resulting in high mortality rate. The study was conducted to investigate the change in haematological parameters with effective anti-tuberculosis therapy. Methods: A total of 45 active tuberculous patients and 45 age and sex matched healthy controls were enrolled for study by convenient non-probability sampling. Patients were taken from Military Hospital, Rawalpindi, whereas controls were taken from community. All the subjects underwent blood sampling for complete blood picture. The samples were taken in ethylene diamine tetraacetic acid (EDTA) treated tube and were analysed in KX-21 Sysmex® automated haematology analyser. Differential leukocyte count was done manually by microscopy of Leishman’s stained blood films. Statistical analysis was done and p