The aim of the study is to determine the stress level among the adult residents of Tri-City (Gdańsk, Gdynia, Sopot), Kielce and Lviv. The study was conducted in January and February 2022. Use was made of a short questionnaire of 25 closed questions, including two scalograms (one covered 10 questions on the sources of experienced anxiety, and the other one was also a 10-item PSS-10 test – Perceived Stress Scale). In the analysis, Kruskal-Wallis H and Wilcoxon-Mann-Whitney tests were applied. In the case of obtaining a statistically significant result of intergroup comparisons, post hoc tests were conducted in order to minimize the error resulting from unequal sample sizes. The stress index level measured by the PSS-10 test amounted to 15.71 in the entire sample, and it was significantly lower among the inhabitants of Lviv (11.94) than in Tri-City (18.07) and Kielce (17.09). When asked about concerns related to the COVID-19 epidemic, the respondents provided different answers depending on the country they lived in. Among the sources of perceived anxiety, residents of Polish cities indicated other people’s attitudes (Tri-City – 55.1%, Kielce – 58.7%) and difficulties in access to health services (64.0% – Kielce, 41.3% – Tri-City). A major source of anxiety for the inhabitants of Ukrainian Lviv, however, was the health of relatives (53.2%) and their own health (49.9%).