peer reviewed ; The implementation of environmental protection policies in Flanders and Wallonia (Belgium) is investigated, looking at the stages of application and the roles of the actors involved. The factors which intervene in the implementation of a European policy, whose characteristics include reformulation at local level, are identified. Structural and political factors affecting change in agricultural and environmental policies are outlined, including regionalization and the division of responsibilities. The example of Belgium shows how it is important that each authority can redefine its own interests in defending the environment using its own resources and contacts. Implementation at local level implies a series of re-interpretations of each agri-environmental measure in the light of expectations and the reactions of land-users.