The characteristic feature of the contemporary economic reality is growing internationalisation of enterprises. This applies to all sectors, including the service sector. Of key importance in the process of internationalisation of service enterprises are the motives impelling businesses to undertake expansion to foreign markets, as well as the factors (criteria) serving the evaluation and comparison of the target markets. The aim of the article is to analyse the determinants affecting the propensity of foreign service entities to undertake expansion into the Polish market and the strategies undertaken in this field, as well as to identify the key sources of competitive advantage taking place at the enterprises in question. The grounds for deliberations in the article arefindings of the research carried out in 2017, among managers of 153 foreign service enterprises operating in the Polish market, of different sizes and scopes of activity. In this article, the author focused on two issues: evaluation of the factors describing the Polish market from the point of view of their impact on the propensity to run their activities therein, as well as identification of the sources of competitive Edge used by foreign service entities. The findings of the conducted research show a positive perception by foreign service enterprises of a prevailing majority of the factors characterising the Polish market. And there are no significant differences between the appraisals made by individual categories of enterprises. In this research, the author identified fourteen sources of competitive edge of foreign service enterprises in Poland. The key one is professionalism in customer service. An important role is also played by brand and accompanying reputation , as well as promptness of customer service and efficacy of marketing measures, mainly promotional ones.