Chronic generalized periodontitis ranks second in prevalence among diseases of the maxillofacial region in the world. The high importance of the problem of the incidence of chronic generalized periodontitis among modern society is determined by early tooth loss, decreased chewing efficiency, and the formation of chronic foci of infection. It is known that the main factor in the etiology of chronic periodontitis is microbial. One of the representatives of this flora is Tannerella Forsythia, which is a gram-negative, anaerobic bacterium. The aim: to verify T. Forsythia in chronic generalized periodontitis, depending on the severity of the disease. Materials and methods: the total number of patients with chronic generalized periodontitis for scientific research was 126 patients. The patients of all the studied groups were taken from the periodontal pocket, and the control group had the contents of the gingival furrow. All samples were examined by PCR with the detection of results in real time on the DT-96 detecting amplifier of NPO DNA Technology LLC with the Periodontoscreen kit. The results of the study: the value of the correlation coefficient was 0.997 p(0.05), which indicates a direct strong relationship between the occurrence of this microorganism and the severity of the disease. Based on the conducted study, a direct strong relationship (0.948 p(0.05)) was revealed between the concentration of the genomic equivalent of Tannerella Forsythia and the severity of chronic periodontitis. Conclusion: as a result of the study, a direct correlation was found between an increase in the genomic equivalent and an increase in the degree of destructive changes in periodontal tissues. Thus, the results obtained confirm that the concentration of Tannerella Forsythia is a predictor of the severity of chronic periodontitis.