Nuclear transcription factor B (NF-B) regulates innate and adaptive immunity functions and mediates inflammatory responses by activating proinflammatory cytokine gene transcription. TNF inhibitors block the NF-B signaling pathway, thus reducing inflammatory activity. The aim of the study was to evaluate the informativity of NF-kB transcription factor determination in the lymphocyte populations in children with inflammatory bowel disease (IBD) and psoriasis to assess the efficacy of anti-TNF therapy. We have examined 124 children with IBD and 55 children with psoriasis vulgaris administered maintenance anti-TNF therapy, and 30 healthy children. Stratification into the study groups was carried out according to PCDIA, PUCAI, PASI indices ( 10, remission). The number of cells with NF-B translocation was determined by flow cytometry with vusualization (Amnis ImageStreamX Mk II). Statistical evaluation was performed using Statistica 10.0 and SPSS 16.0. The highest number of cells with NF-B translocation was detected in B-lymphocytes and NK cells, thus being significantly higher than in T helper cells and cytotoxic T lymphocytes (p = 0.000). The percentage of cells with translocation of NF-B in populations of NK cells, T helper, cytotoxic T lymphocytes, Th17 lymphocytes, cytotoxic Th17 lymphocytes (Tc17) and Treg was increased in the patients at the acute disease stage against the comparison group. In the remission state, NF-B activity in lymphocyte populations was lower than in acute stage. In remission of psoriasis, NF-B activity in B lymphocytes, NK cells, and cytotoxic T lymphocytes was significantly lower than in comparison group. In IBD remission state, the NF-B activity was elevated only in T-helper cells. The level of NF-B translocation in the NK-cell population differed in children with IBD and psoriasis, both in acute phase (IBD, 46.2% (34-58); psoriasis, 36.5% (29-48), p = 0.041), and remission of disease (IBD, 25.4% (22-35); psoriasis, 19.1% (17-22), p = 0.000). ROC analysis of the data from exacerbation/remission states assessed as the NK cell numbers with NF-B translocation showed a good quality of the stratification model (AUC 0.8): The cut-off value in IBD was 41% (Se = 65.4; Sp = 89.1), and in psoriasis it was 23% (Se = 85.2; Sp = 94.7). The informativity of NF-B translocation level in lymphocyte populations in children with IBD and psoriasis was shown to correlate with efficacy of anti-TNF therapy. Exacerbation the disease with decreased therapeutic response is characterized by NF-B activation in lymphocyte populations in the children with IBD and psoriasis.