Objectives: In addition to physical damage, COVID-19 also has a serious impact on the mental health of society. For many people, this involves the necessity of adapting to new conditions, uncertainty about the future and a tremendous mental burden. It was investigated whether there were any differences between the 2 measures (before and during the COVID-19 pandemic) in the levels of perceived stress, anxiety, life satisfaction and experienced emotions. Material and Methods: The study, conducted in Poland and the Netherlands, involved 168 people. The metric, the Positive and Negative Experience Scale, the Perceived Stress Scale, the and the Satisfaction With Life Scale were used. The subjects were divided into 3 groups: non-immigrants living in Poland (N = 50), Dutch citizens (N = 56), and Polish immigrants living in the Netherlands (N = 62). Results: The level of stress and negative emotions was higher in the groups of Poles living in Poland and Poles living in the Netherlands than in the group of Dutch citizens. Therefore, access to psychological care should be improved during the pandemic, especially for immigrants, due to the increased risk of developing stress-induced mental disorders. Conclusions: In the groups of Poles, there was an increase in perceived stress and trait anxiety during the COVID-19 pandemic. The group of Dutch citizens experienced a reduction in the anxiety level during the COVID-19 pandemic. In the group of Polish immigrants, there was an increase in life satisfaction during the COVID-19 pandemic. Int J Occup Med Environ Health. 2021;34(2):177–88