This thesis investigates changes in consumer habits in retail chains during the COVID-19 pandemic and the adjustments of marketing activities to these changes. The aim of the research is to gain a deeper understanding of consumer habit changes and identify the strategies that retail chains have employed to adapt to the new circumstances. The research methods include analysis of professional and scientific literature, synthesis, induction, deduction, description, comparison, and compilation. A survey questionnaire was also used to collect data from consumers. The results of the survey analysis show that the majority of respondents prefer online shopping during the pandemic. Additionally, there is a shift in consumer attitudes and preferences, as well as a sense of insecurity when shopping in physical stores. The costs of shopping have also changed, and most respondents plan to return to their usual shopping habits after the pandemic. Overall, the research confirms the working hypothesis that consumers have changed their shopping habits during the COVID-19 pandemic. Furthermore, the auxiliary hypothesis regarding the preference for online shopping compared to physical stores during the pandemic is also confirmed. This study provides relevant insights into changes in consumer behavior and the adaptations of marketing activities in service businesses during the COVID-19 pandemic.