ABSTRACT Aims of Study: To compare dynamic thiol/disulfide homeostasis between patients with with lung tuberculosis and healthy controls. Methods: Our study included 50 patients with active lung tuberculosis and 50 healthy controls. Serum thiol/disulfide was measured with a new automated spectrometric method developed by Erel and Neselioglu, and results were compared statistically. Results: We found that native and total thiol levels were significantly decreased in patients with lung tuberculosis, disulfide/native thiol and disulfide/total thiol levels were found to be higher in lung tuberculosis patients when compared with the control group. However, disulfide levels were higher in the control group than in the patient group. Conclusions: Based on the results of this study, it can be said that oxidative stress is closely associated with lung tuberculosis pathogenesis. There is a need for new studies that will show the possible effects of oxidative stress on lung tuberculosis pathogenesis.