Introduction. This article, using a clinical case as an example, reflects the problem of the development of tumor lysis syndrome (TLS). The most common cause of SLO development is antitumor treatment: radiation therapy, radiofrequency ablation, vascular embolization, the use of monoclonal antibodies, high-dose chemotherapy with transplantation of stasis from peripheral blood. This disorder leads to the development of metabolic, hemodynamic, respiratory and renal disorders. The TLS distinguished by high mortality rates, from 17% to 70%.Materials and methods. Presented a clinical case of patient, 30 years old - observation of successful treatment of TLS of the III degree of clinical course according to Cairo-Bishop, in the conditions of the State Budgetary Healthcare Institution «Chelyabinsk Regional Clinical Center of Oncology and Nuclear Medicine», in the conditions of the intensive care unit and intensive care with the use of renal replacement therapy on the Prismaflex device.Results and discussion. When the patient applied to the State Budgetary Healthcare Institution «Chelyabinsk Regional Clinical Center of Oncology and Nuclear Medicine», the diagnosis made — Non-Hodgkin lymphoma with a diffuse type of growth of a high degree of malignancy. Revealed the defeat of the lymph nodes, parietal pleura, right hemithorax, atelectasis of the middle lobe of the right lung with air bronchography, hydrothorax on both sides, hydropericardium, free fluid in the pelvic cavity, phlebolitis of the parametric tissue, degenerative-dystrophic changes in the spine. On the first day of hospitalization, antibacterial and pain relief therapy started, and nutritional disturbances were corrected. After the pre-phase chemotherapy (cyclophosphamide, vincristine), the patient's condition worsened, she was transferred to the intensive care unit. Where was the treatment carried out: convulsive syndrome, respiratory failure, acute renal failure, bilateral pneumonia, PE. Against the background of this therapy, special treatment continued - 2 cycles of chemotherapy. After the patient transferred to spontaneous breathing and the indices of blood slags and potassium were normalized, she was transferred to the antitumor therapy department to continue special treatment. Conclusion. Our algorithm for the treatment of SLO led to positive dynamics and the possibility of carrying out special antitumor therapy for this patient.