The aim of this article is to determine whether and to what extent political polarisation on the domestic party scene determines the ability of the Polish national delegation in the European Parliament (EP) to shape voting patterns. This problem is presented using the example of Poland. The approach presented in this article is original and scientifically significant. First, previous analyses of the implications of political polarisation are usually limited to presenting them in relation to the political system of a given country. Second, research on the coherence of voting in the EP is mostly devoted to political groups, i.e. the relevant actors, who are responsible for stimulating political processes in the EP. The presented approach is not reflected in existing studies on either polarisation or the EP, thus constituting a new research proposal. It has been proven that the catalogue of determinants conditioning the coherence of votes should include political polarisation. The study shows that there is a negative correlation between the variables, which means that an increase in the level of polarisation is associated with a decrease in the coherence of votes of the Polish delegation in the EP. And vice versa – a decrease in polarisation at the national level is accompanied by an increase in the ability of the Polish representation in the EP to reach agreements beyond factions. The presented findings undoubtedly require further verification on a wider set of EU countries.