The patients with multiresistant tuberculosis were divided into 2 groups: the sensitivity of Mycobacteria tuberculosis to antituberculous drugs was evaluated in Group 1 by the methods of absolute concentrations and in Group 2 by biological microchips determining mutations in the rpo3 gene responsible for rifampicin resistance. The results of the drug sensitivity test were obtained after 3 months of treatment in Group 1 and several days prior treatment in Group 2. By taking into account the test results, reserve drugs was used in Group 2 patients. Subsequently, the results of the drug sensitivity tests carried out by the bacteriological method in Group 2 patients showed that isoniazid resistance was simultaneously noted if there were mutations in the rpo-B gene. Timely treatment with reserve drugs exhibited higher efficiency of treatment with its shorter duration in Group 2 than in Group 1.