Nearly 15 years ago we witnessed one of the most important events in the history of the European integration – the enlargement of the European Union by 10 new Member States, including Poland. It was a remarkable event both from the perspective of our country and region, as well as that of the whole continent, with its historical significance placing it among the most important events in recent history. The upcoming 15^th anniversary of the biggest enlargement in the history of the EU is an excellent opportunity to summarise its outcomes. We would like this conference to serve as an opportunity to analyse the results and to review the state of the European integration process itself as well as the challenges that lay ahead for the European Union and its MemberStates.