BACKGROUND: Interferon-gamma (IFN-g) and tumor necrosis factor-alpha (TNF-a) play a critical role in protective immunity against Mycobacterium tuberculosis infection. (The change )of IFN-g and TNF-a producing capacity in the course of antituberculous chemotherapy in patients with pulmonary tuberculosis (was evaluated in this study.) METHOD: In 29 patients with pulmonary tuberculosis, phytohemagglutinin(PHA) or purified protein derivative(PPD) stimulated production of IFN-g and TNF-a by peripheral blood mononuclear cells was quantified. Five patients were sampled before they underwent antituberculous treatment, 11 patients after 0 -4 months, six after 4 -completion and seven after treatment completion. RESULT: There was no difference in PHA- or PPD- stimulated production of IFN-g and TNF-a between each group. CONCLUSION: No difference in PHA- or PPD- stimulated production of IFN-g and TNF-a between two groups could be identified during classification of patients with pulmonary tuberculosis by their treatment stages.