The EU’s Common Agricultural Policy (CAP) is an example par excellence where reform has proven to be difficult and incremental in the face of a powerful agricultural policy network. Nevertheless, the increasing multidimensionality of agriculture, linking the domain with environmental, trade and food safety concerns, has mobilised new policy actors bringing new preferences and ideas into the CAP debate. This paper will investigate the extent to which this has resulted in Environmental Policy Integration (EPI) in the CAP. It will build on and add to existing analyses which tend to focus on single cases or certain dimensions of EPI only, by providing a longitudinal comparative analysis of the CAP reforms over the last two decades. This analysis will furthermore be based on a multidimensional concept of EPI as process (the formal and informal institutions in place allowing the integration of environmental concerns), output (the translation of such concerns in changes in policy settings, instruments and objectives), and outcome (the performance of the new policies in terms of environmental benefits).