The 4th workshop on the Impact of the Public-Private Partnership "Factories of the Future" (FoF PPP) was organised in March 2014, by the European Commission with the support of the European Factories of the Future Research Association (EFFRA). All FoF projects originating from calls between 2010 and 2013 were invited to a 2-day event to assess the impact of the PPP initiative and to strengthen the cooperation links within the community. Building on the progress of the activities promoted at the 3rd workshop in March 2013, this workshop focussed on increasing cross-project clustering. Differently from the previous year, the projects were grouped thematically, rather than by the call topics themselves. Joint presentations were prepared and delivered in three parallel sessions, where discussions were encouraged to further identify common synergies and ideas. The second day was organised as a plenary session, with keynote speakers from the EC and the industry, and where success stories were presented, followed by a panel of EC and private sector representatives talking about their views on the Factories of the Future PPP.