The evaluation of the thiol-disulfide homeostasis is important to assess the level of the oxidative stress (OS) in patients with pulmonary tuberculosis (PTB) for early detection of metabolic disturbances. Aim: to evaluate the content of thiol-disulfide groups in the serum of the patients with different types of PTB. Methods and materials: a prospective cross-sectional research, which quantified the serum concentration of thiol-disulfide groups (-SH groups) in 137 patients with PTB was conducted. The patients were distributed in the 1st study group (SG) - 54 new cases with drug-susceptible TB, the 2nd SG -56 new cases of multidrug-resistant TB (MDR-TB) and 3rd SG-27 previously treated with acquired MDR-TB. The groups were compared between them and were compared with a control group (CG) composed of 36 conventional healthy persons. Samples of venous blood were collected, centrifuged for 10 minutes at speed 3500 rpm, with further separation of the serum. The serum content of –SH groups were quantified using the method of G.L. Ellman and Hu M.L modified [1, 2]. Obtained results established a significant decrease of the –SH groups content in serum of patients from all study groups by 20%, 25% and 25% in the 1st , 2nd and 3rd groups respectively compared with CG, without statistical differences between the study groups. The most pronounced decrease was registered in the 3rd SG. In conclusions, the reduced content of the–SH groups reflects the depletion of thiol-disulfide system and can be used to assess the metabolic disturbances in patients with PTB.