The pattern of clinical forms of respiratory tuberculosis in children shows a preponderance of intrathoracic lymph node tuberculosis (89.4%) that is characterized by a complicated process in every third child under present-day conditions. Positive result of PCR closely correlates with the severity and extent of the specific process in children. Real-time PCR (RT-PCR) was ascertain to exhibit the highest sensitivity in detecting Mycobacterium tuberculosis DNA in children with primary generalized tuberculosis (62.5%) and in those with a disseminated specific process (55.6%), which was much higher than conventional bacteriological study of diagnostic materials. By taking into account the findings, the RT-PCR detection of M. tuberculosis was considered as a substantial criterion for evaluating the magnitude of specific changes and the degree of tuberculosis infection activity in children.