BACKGROUND: Non-invasive methods for diagnosing thyroid pathology with an inapparent, asymptomatic or clinically non-specific course is an urgent task of thyroidology today. It seems promising for such diagnostics to use a combination of mass spectrometry of microbial markers of the human intestinal microbiota with an assessment of the quality of life using the 36-Item Short Form Survey (SF-36) questionnaire. AIM: to study the features of intestinal microbiocenosis and subjective assessment of the quality of life in patients with thyroid diseases. MATERIALS AND METHODS: 21 patients were examined (8 men and 13 women, median age 40,5 [31,75; 54] years, respectively; 15 with thyroid disease of varying degrees of clinical manifestations, 6 without thyroid disease). In addition to the standard clinical and laboratory-instrumental examination, the patients underwent a study of the contents of the large intestine by the method of chromato-mass spectrometry of microbial markers. Through the use of the SF-36 methodology, an assessment of the quality of life was implemented. Descriptive, nonparametric statistics were used in the work, differences in relative frequency values were determined using Fishers exact test. The presentation of the results was carried out using range diagrams, compactly depicting a one-dimensional probability distribution, tables. RESULTS: Differences in the composition of the microbiota of the control group and the study group for Alcaligenes spp., Staphylococcus spp. were revealed, a downward trend in the level of Megamonas hypermegale, Peptostreptococcus anaerobius in the main group is determined. A tendency revealing a decrease in the quality of life in the study group compared with the control in terms of social functioning, role emotional functioning was revealed. CONCLUSIONS: Pathology of the thyroid gland is accompanied by deviations in the composition of the fecal microbiota, determined by the method of mass spectrometry of microbial markers. Characteristic features of changes in the intestinal microbiome are a decrease in the level of Alcaligenes spp., Staphylococcus spp., a tendency to decrease in the titers of Megamonas hypermegale, Peptostreptococcus anaerobius. Violation of the endocrine function of the thyroid gland can cause a deterioration in the quality of life, which is manifested by a tendency to reduce social functioning, role-playing emotional functioning.