Objective: To study the informative value of the detection of mycobacteria in blood with the cultural method in patients with suspected tuberculous sepsis and to determine the most significant clinical and laboratory criteria for testing. Materials and methods: The investigation to detect M.tuberculosis was fulfilled in 159 HIV-positive patients with suspected tuberculosis sepsis. Blood culture was completed with culture medium Myco/F Lytic Culture Vials and analyzer BACTEC 9050. Results: Mycobacteria were detected in blood of 19 patients (11,9% of all patients): in 18 patients the growth of M. tuberculosis complex was detected (25,3% of all patients with diagnosed tuberculosis) and in 1 patient it was Mycobacterium avium complex (0,6% of all patients). It was shown, that the probability of M.tuberculosis detection was especially associated with the severity of the disease, immunosupression (less than 100 cells/mkl), hemoglobin quantity less than 90 g/l (levels were determined through the seeking for the most significant cutoffs). It was not proofed, that meningoencephalitis develops more often in patients with proven bacteremia. There were no evident differences in detection frequency of mycobacteria in sputum between patients with tuberculous sepsis and without it.