Tuberculin skin test has been used for many years for the diagnosis of latent tuberculosis infection. The aim of this study was to compare the effectiveness of tuberculin skin test (TST) and QuantiFERON-TB (QFT) in diagnosing latent and active tuberculosis. A total of 53 patients were evaluated in this study. Group I consisted of 21 patients with primary active tuberculosis. Group II consisted of 20 patients who were TST positive (TST>15mm) and Group III consisted of 12 patients who were TST negative (TST<5 mm). TST and QFT were applied to all patients. The QFT test showed positive result in seven, negative in two and no mitogen stimulus in 12 of patients with active tuberculosis (Group I). In Group II, all patients but one showed positive QFT test. QFT test was found as negative in 11 of 12 patients with TST negative (Group III). The QFT test was of no use in the majority of patients with active tuberculosis as they failed to demonstrate mitogen stimulus. However, in other patients, the QFT test results were found to be comparable with TST.