April 25, 2005 (, Yiyou March 17), Bulgaria and Romania signed a treaty to join the European Union in Luxembourg. Reference April 25, 2010, Bulgaria and Romania signed a treaty to join the European Union in Luxembourg. These two countries on January 1, 2007 to join the EU, the EU has 27 member states and a population of over 480 million regional integration organizations. Pictured April 25, 2005, European Commission President Jose Manuel Barroso (left), held in Luxembourg, Bulgaria and Romania signed the accession to the EU treaty ceremony on speech.