Currently, there are no comprehensive studies to assess the causes of adverse reactions in terms of the use of omalizumab. The aim of the study was to conduct a comprehensive analysis of the causes of adverse reactions to omalizumab. Materials and methods. Based on these criteria, experts of medical organizations conducted a retrospective assessment of 300 cases of omalizumab use with registration of existing defects based on the data of primary medical documentation (inpatient records, outpatient records). By the method of a sociological survey of 100 doctors, the level of their awareness of the procedure for reporting adverse reactions of drugs and, in particular, omalizumab was studied. The data were processed using applied computer programs. Outcomes. The incidence of medical-organizational defects in safety monitoring of omalizumab was 591 per 100 cases overall. The highest frequency was observed in such defects as: "lack of analysis of identified adverse reactions and cases of ineffectiveness"; "lack of a plan for corrective and preventive measures in connection with the detection of cases of adverse drug reactions"; "violation of the deadlines for the transfer of notices". In the structure of defects in reporting and filling out notifications of adverse reactions of omalizumab by doctors of medical organizations, the leading positions are occupied by: the absence of indications of the presence of bad habits (drug addiction, alcohol abuse, smoking) in the patient; absence of indications of the patient's reaction to the drug; lack of information about the period of time that has elapsed from the administration of the drug to the onset of symptoms of an adverse reaction. The weakest points of professional awareness of doctors about the procedure for reporting adverse reactions of omalizumab are: awareness of the need and content of the analysis of the identified adverse reactions; on regulatory documents on the quality, efficacy and safety of medicines; on the notification scheme of the person responsible for monitoring the safety of the medicinal product.