The service sector has become the dominant sphere of market economies over the last forty years. The maturity of a country’s economy is directly related to the maturity of services as an economic sector. The immense growth across the service sector has also put mounting pressure on the competitiveness of service enterprises and their marketing activities. The turn of the millennium has already seen the competitive struggle affected by two crises – first, an economic one and now, one caused by the Covid-19 pandemic, which has had a great impact (not only) on the service sector. The article deals with the question of how Czech service enterprises reflect on the impact of the pandemic. The article’s aim is to find out how service enterprises perceive the impact of the Covid-19 crisis depending on their size and classification within the service sector and how they approach marketing investments during a pandemic crisis. The research is focused on service enterprises (n=90) in terms of their application of marketing processes in the conditions of the Czech Republic in the period 2020-2021. The results, based on descriptive and inferential statistics (ANOVA test in conjunction with Hochberg and Games-Howell tests, Pearson’s correlation coefficient and chi-squared test), show that smaller enterprises tend to be more affected by the effects of government measures in the context of the Covid-19 crisis than medium and large enterprises.