Background: Interferon gamma (IFN-γ), a cytokine produced by a variety of cells is involved in the immune response against M.tuberculosis. It activates the production of other cytokines & molecules that kill MTB. IFN-γ also has diagnostic role in identification of active and latent TB. Objective: To determine the level of IFN-γ in the blood of TB patients. Methods: 91 subjects were selected, including 54 active TB patients and 37 healthy controls. IFN-γ conc. was determined in their blood by ELISA technique. Results: In TB patients, Mean+SD of IFN-γ was 48.69+28.78 while it was 12.99+5.70 pg/ml in control group (p <0.001). Significant differences in the level of IFN-γ were observed among confirmed TB patients, clinically diagnosed TB patients and the control group (Mean+SD 59.68+28.78, 36.85+24.76 and 12.99+5.70 pg/ml, respectively). Furthermore, a significant negative correlation was observed b/w conc. of IFN-γ in TB patients and the duration of anti-tuberculosis therapy. Conclusion: IFN-γ level was high in both clinically diagnosed and confirmed TB patients as compared to a control group. Measurement of IFN-γ is helpful to diagnose active TB, but further research is required.