The article analyses the role played by the Polish diplomacy in the process of developing and implementing the eastern policy of the European Union. Following a presentation of the relevant definition of this policy, as well as its main aims, the geographical and time framework, the author discusses the essential historical determinants that condition its present shape. This has been shown against the background of broader instruments of EU foreign policy, first of all the European Neighbourhood Policy. The EU Eastern Policy is one of the two essential components of the ENP, further divided into strategic partnership with Russia and a new instrument, the Eastern Partnership. The aims, instruments and principles of the latter have been discussed in more detail. The primary topic of the article, however, emphasises the role of Polish diplomacy, for which active participation in the development and implementation of the EU Eastern Policy is one of the key elements securing Poland’s national interests. In this context the author has shown the main Polish political and diplomatic initiatives and undertakings, especially the initiative of establishing the Eastern Partnership. The article ends with a brief attempt to evaluate the achievements and shortcomings in this regard, as well as to out¬line some forecasts.