Acute coronary syndrome is a clinical condition caused by sudden, critical ischemia of the myocardium and includes two entities: unstable angina pectoris and myocardial infarction and is most often the result of rupture of an atherosclerotic plaque. On March 12, 2020, the World Health Organization declared a pandemic of the disease COVID-19 caused by the SARS-CoV-2 virus. Clinical presentation can be asymptomatic but development of pneumonia with severe acute respiratory insufficiency is also a possibility, as well as the appearance of neurological symptoms and destabilization of the atherosclerotic plaque with the development of acute coronary syndrome or the development of myopericarditis, the occurrence of heart rhythm disorders and arterial hypertension with potential lethal outcome. The aim of this is paper is to examine whether the incidence of acute coronary syndrome increased during the COVID-19 pandemic along with the change in patient demographic characteristics. The research will also provide an answer in which time interval after the infection caused by the COVID virus, acute coronary syndrome most often developed. A retrospective study of medical records was conducted in all patients who were treated for acute coronary syndrome in 2018 (before the pandemic) comparable to the data in 2021 (during the pandemic). The incidence of acute coronary syndrome and the structure of patients were compared, taking into account age, gender and comorbidities. In patients with acute coronary syndrome during the year 2021, the time relationship between the onset of acute coronary syndrome after recovery from the infection caused by the COVID-19 virus was taken into account.