The introduction of modern nursing technologies contributed to an increase in the survival rate of premature newborns, which led to an increase in the population of children with long-term pulmonary complications. Despite the large amount of literature data, the pathogenetic mechanisms contributing to chronic lung disease after premature birth, especially in the issue of dysregulation of the immune system, are not fully understood. In order to identify clinical and immunological risk factors for the formation of severe bronchopulmonary dysplasia (BPD) in children with extremely low body weight (ELBW), 36 children with BPD and 34 children without BPD were examined. Phenotyping of monocytes and lymphocytes was performed by flow cytometry on a FACS Calibur analyzer (Becton Dickinson, USA) using monoclonal antibody kits from the same manufacturer. Statistical processing of the study results — using the programs Excel and Statistica 6. Differences between the groups were established using the χ² test, Student’s (T-test) and Mann Whitney (Mann-Whitney U-test). The level of significance of intergroup differences (p) was taken less than 0.05. In children with severe BPD, at birth there is a decrease in the relative number of cells expressing receptors TLR2, TLR4 CD14⁺CD11b⁺ and CD3⁺, CD4⁺, CD8⁺ lymphocyte populations; an increase in the number of regulatory CD4⁺CD25⁺ cells and the production of IFN-γ, IL-8 against the background of a low content of anti-inflammatory IL-4. In the postnatal period — a decrease in the production of IL-4 and an increased content of IL-8 in 1 month of life, persisting up to PCV 37-40 weeks. At the age of a full-term baby of weeks — an increased number of CD4⁺CD25⁺ and CD16⁺CD56⁺ cells. Risk factors for severe BPD in children with ELBW have been identified — low Apgar score at 1 minute of life, birth weight, duration of invasive respiratory support, presence of pneumonia and sepsis, IVH of varying severity, ineffectiveness of phagocytosis processes, direction of cell differentiation on the Th-1 pathway in the neonatal period. Our data indicate a pronounced immunosuppression and pro-inflammatory status of children with ELBW who have developed severe BPD. Further understanding of the role of immune dysregulation in the pathogenesis of severe BPD makes it possible to develop immunosuppression-related strategies for the prevention and treatment of this disease.