Can environmental policy innovations be successfully implemented in different nation-states through organized international policy transfer? And what role do international and national factors play in this transfer process? Ralf Nordbeck answers these questions by examining the implementation of the international environmental action program for Central and Eastern Europe in 22 Central and Eastern European countries. The diversity of national adaptation responses ranges from the successful adoption of policy innovation to the refusal of policy transfer. Using a combination of macro-qualitative analysis and four detailed case studies, the causally relevant conditions that determine the success of a national environmental action program are identified: the willingness of actors to innovate in environmental policy and structural innovation.