Background: COVID-19 vaccines for public use were approved at the turn of 2020 and 2021. The level of vaccination coverage against COVID-19 in Poland is one of the lowest in Europe. Despite scientific studies there are people who are afraid of vaccinations and spread false information about them. Vaccinations against COVID-19 allowed us to learn about the attitudes of people who decided to be vaccinated, which can be used to improve the effectiveness of the infectious diseases prevention in the work and public environment. The aim of the study was to analyze the main reasons determining a decision to get vaccinated against COVID-19. Material and Methods: The study was carried on among all the people who decided to be vaccinated against COVID-19 in Nofer Institute of Occupational Medicine in Łódź. All vaccinated people completed an anonymous survey containing questions related to the most important factors, which encouraged them to undergo this vaccination. Results: The study involved 945 people vaccinated against COVID-19. Statistical significance was revealed between 3 different reasons (one’s own health, stress-free work, safe travelling and easier access to entertainment) for getting vaccinated and age, gender and a form of employment. The authors also found statistical significance of the correlation between the age, gender, education and form of employment of the respondents and the reason for choosing the specific vaccine product. Conclusions: Despite evidence presented by scientists about the effectiveness and safety of vaccinations, many people refused and still refuse to receive the vaccine. In order to increase the readiness of the population for vaccinations against COVID-19 and subsequent ones, if there is a need to limit new epidemics, the following should be done: introduce activities to raise health awareness, intensify strategies and campaigns aimed at increasing public trust in available vaccines against COVID-19, devolop individualized messages that contribute to vaccine hesitancy.