The prevalence of drug-resistant tuberculosis in the Republic of Tatarstan was studied. Among the bacillary patients with tuberculosis, those who isolated drug-resistant Mycobacterium tuberculosis were 54.4%; primary drug resistance was detected in 31.5% of the patients. In the pattern of drug resistance, multidrug resistance was predominant (47.3-75.4%) in all the categories of patients. Whether the blood bacteriostatic activity (BBA) could be used to correct a chemotherapy regimen in patients with tuberculosis was studied. A direct relationship between the level of BBA and a clinical effect was found in new cases of patients. When BBA was low, the treatment regimen required correction in order to achieve the higher level of BBA. There was no relationship between the level of BBA and the results of treatment in patients with chronic tuberculosis. The low values of BBA seen in the use of reserve drugs cast any doubt on the expedience of their use in chronic tuberculosis.