Most previous analyses of Poland’s planned accession to the euro zone focused on the macroeconomic aspects of the move, while overlooking its microeconomic significance. The authors of this paper are concerned with the impact of euro adoption on the competitiveness and internationalization of enterprises. The basic question that they attempt to answer is how euro-zone entry will change the conditions in which Polish businesses operate, and how it will change the range of instruments companies use in the process of building a competitive advantage and in shaping their competitive strategies. Gorynia, Jankowska, Pietrzykowski and Tarka conducted empirical research among 50 enterprises in the western Polish region of Wielkopolska. They divided the companies into four groups by employment. Most of the companies supported Polish euro-zone entry, but the level of acceptance depended on the strategic potential of an enterprise. According to respondents, lower currency risk would be the most important benefit of the move, while the main threat is that soaring prices could harm domestic demand. The results of the research contribute to a nationwide debate on the implications of Polish entry into the common currency area. According to the paper’s authors, research in this area should be continued to cover not just individual regions but the whole country.