The objective: to study the efficacy of tuberculosis preventive chemotherapy in HIV infected patients based on the data of AIDS Prevention and Control Center, which is a part of City Infectious Clinical Hospital no. 1, Novosibirsk.Subjects and Methods. 236 HIV infected patients aged 33-48 years old were enrolled in the study, they all were registered in AIDS Prevention and Control Center, City Infectious Clinical Hospital no. 1, Novosibirsk. All patients were at the stage of secondary diseases (4A, 4B, 4C), and had a pronounced degree of immunodeficiency (CD4+ from 200 to 349 cells/µl), and the ongoing ART was virologically successful. The efficacy of tuberculosis preventive chemotherapy (CTX) was analyzed in 147 patients versus 89 patients who received no tuberculosis CTX due to various reasons. For tuberculosis preventive chemotherapy, a combination drug was used, which contained isoniazid and pyrazinamide, for 3 months with daily intake. The groups of those receiving and not receiving CTX were comparable in terms of the gender, age and degree of immunodeficiency.Results. In the group receiving CTX within a year after completion of CTX, tuberculosis was diagnosed in 7/147 (4.8%) patients including: focal pulmonary tuberculosis - in 71.4% (5/7), and infiltrative pulmonary tuberculosis - in 28.6% (2/7 patients). In the group receiving no CTX, during the year, 17/89 (19.1%) tuberculosis cases were detected: focal pulmonary tuberculosis – in 29.4% (5/17), infiltrative pulmonary tuberculosis - in 47.1% (8/17), and disseminated pulmonary tuberculosis - in 23.5% (4/17). Disseminated pulmonary tuberculosis was registered only in the group who received no CTX. The relative risk (RR = 0.442 (<1)) when comparing the number of cases in the groups indicates lower likelihood to develop tuberculosis in the patients taking CTX. The odds ratio (OR = 0.212; CI 0.084-0.534) indicates that the chances of developing tuberculosis are higher in the group receiving no CTX.Conclusion. The use of a combination of isoniazid and pyrazinamide for tuberculosis preventive chemotherapy in HIV infected patients significantly reduces the risk of developing tuberculosis. Patients with severe immunodeficiency who have contraindications to tuberculosis preventive chemotherapy should be followed up jointly with a phthisiologist, the follow-up should include computed tomography for early detection of tuberculosis signs in the lungs.