BACKGROUND: Over the past decades, the incidence of primary biliary cholangitis (PBC) has increased worldwide. The disease is characterized by relentless progression and, if not diagnosed promptly, leads to liver cirrhosis and liver failure. The etiology of primary biliary cholangitis remains unknown; however, in addition to the hereditary factors and environmental triggers, microbiotic disorders caused by periodontopathogenic bacteria that contribute to the development of inflammatory and destructive processes in the oral cavity are of particular importance in its pathogenesis. AIM: This study aimed to determine the major periodontopathogens of the oral cavity in female patients with PBC and to compare their species composition with the disease stage and liver stiffness values. METHODS: In a case–control study, we examined women with PBC (the main group) and women without liver disease. Based on transient elastography and laboratory liver function tests, patients with primary biliary cholangitis were divided into two subgroups: those with early and late stages of the disease. The threshold liver stiffness value was 9.6 kPa. In patients with PBC, the response to ursodeoxycholic acid therapy was assessed using the Paris II criterion one year after treatment initiation. Material from periodontal pockets was used to detect periodontopathogens. Microbial DNA was extracted using polymerase chain reaction. The results were compared with those in the control group. RESULTS: The main group included 48 women, and the control group included 52 women. A significant increase in the abundance of the most significant periodontopathogenic microorganisms in the periodontal pocket contents was found in patients with primary biliary cholangitis compared to control values. The most frequently isolated DNA was Porphyromonas gingivalis (70.83% of cases), Tannerella forsythia (72.92%), Treponema denticola (64.58%), and Prevotella intermedia (60.42%). When compared with control values, statistically significant differences (p < 0.005) were found for all periodontopathogens studied. Statistically significant differences were found between groups in the average number of periodontopathogens per person and depending on the disease stage in the subgroups of patients with primary biliary cholangitis. CONCLUSION: The established relationship between the microbiotic status of the oral cavity and the stage of primary biliary cholangitis suggests the possible involvement of periodontopathogens in the mechanisms of disease progression, a finding that warrants further research.