A comparative study of differentiation of CD3+CD4+ peripheral blood lymphocytes of healthy volunteers (n=30) and patients with irritable bowel syndrome (IBS, n=22) was conducted using multicolored flow cytometry. In patients with IBS, The level of T-helpers of Central memory (CM), CD45RA-CD62L+ in patients with IBS significantly exceeded the values of the control group. Among the General population of CCR6+ CM Th17 there were significant increases in the percentage of DN Th17 (from 2.58% (1.55; 3.15) to 3.14% (2.53; 4.09) at p=0.011) and Th17.1 (from 9.42% (7,594 10.52) to 10.08% (10.33; 14,48) at p=0,002) when compared with the control. Moreover, IBS showed a change in the subpopulation composition of follicular T-helper cells (Tfh). Thus, in patients with IBS the relative content of Tfh2 cells and not yet described in detail Tfh with phenotype CXCR3+CCR6-CCR4+ decreased, while the level of two populations of Tfh with properties of Th17 (DN Tfh17 and Tfh17.1) significantly increased. The detected changes in