The new coronavirus infection (COVID-19) has become a truly global challenge for all of humanity, and, above all, for the healthcare system. Among its most important aspects requiring careful analysis are the clinical and laboratory features of the course of the disease, which make it possible to determine approaches to pathogenetic therapy in severe forms of the disease. Materials and methods. A retrospective analysis of medical records of patients (n = 31) of severe COVID-19 patients who were hospitalized in St. Petersburg City Clinical Hospital for Infectious Diseases named after S.P. Botkin”in March – May 2020. Clinical and laboratory characteristics were evaluated, including the level of ferritin, C-reactive protein, D-dimer, interleukin-6, depending on the severity of the disease. The criteria for the appointment of a recombinant humanized monoclonal antibody to the human receptor for interleukin-6 (INN – tocilizumab) in patients with a severe course of the disease and its effectiveness are determined. Results. In the treatment of severe patients with COVID-19, it is necessary to carefully evaluate the clinical picture of the course of the disease, which may be ahead of changes in laboratory parameters. The introduction of tocilizumab leads to a rapid regression of general infectious symptoms, subjective and objective manifestations of respiratory failure and, as a consequence, a decrease in the duration of hospitalization. It is extremely important that the drug is administered in a timely manner during the rise of the “cytokine storm”. The time for optimal administration of tocilizumab begins from 8-9 days from the onset of the disease, until the patient is transferred to mechanical ventilation. © 2020 Interregional public organization Association of infectious disease specialists of Saint-Petersburg and Leningrad region (IPO AIDSSPbR). All rights reserved.