Ten Central and Eastern [NLG4] European countries have recently joined the European Union. This historical enlargement provided a good opportunity to discuss the challenges and opportunities in Pan-European Research Collaboration for researchers from Central/Eastern Europe. This paper summarises examples of productive research collaboration between East and West, current challenges [NLG5], and ideas on how to facilitate better collaboration. A short overview of training, mobility and career development opportunities, covered by the Marie Curie actions, is also presented.