A key objective of the EU Framework Programmes for Research and Innovation is the creation of cross-country research networks. We make use of Social Network tools to describe the evolution of the EU research network across countries on the basis of unique data covering collaborative projects launched during the first four years of implementation of Horizon 2020 and its predecessor programmes, the Sixth and Seventh Framework Programme. We describe the positioning of all EU-countries in the collaborative research network, the positioning of the older member EU-15 and the newer member EU-13 countries in particular, and to what extent the network has been subject to change during the period 2003–2017. EU-15 and EU-13 countries have become more ...