Extending the concept of security to sectors other than the military, coincides with the securitization of infectious diseases in the 1990s, making health security one of the most important topics. The outbreak of the COVID-19 pandemic has further potentiated health security in the context of the crisis management approach and the phenomenon of securitization and desecuritization. The aim of this paper is to analyze the approaches in crisis management caused by COVID-19 in Croatia and Serbia and to identify the similarities and the differences in the policies developed in relation to this threat and their application. The paper seeks to answer the question of what the similarities and the differences are in the approach to crisis management caused by COVID-19 in Croatia and Serbia. The analysis of the crisis management approach through the phases of prevention, preparation and response from the perspective of securitization, examines the main hypothesis that there are similarities in the manifestations of this disease and there are also significant differences in policies and actions to combat the COVID-19 pandemic. Due to the complexity and topicality of this topic, the research is limited to the period until the start of vaccination in Croatia and Serbia, i.e. the period of the pandemic in the year 2020. In addition to contributing to further research in the field of health security, this paper makes a particularly important contribution in terms of detecting key lessons that can be used in the following crises.