We illustrate how randomized controlled trials (RCTs) could be used as a learning tool to shed light on various aspects of the Common Agricultural Policy (CAP). RCTs are quasi-absent from the CAP evaluation toolbox, despite their frequent use to evaluate other European Union policies, or agricultural policies in developing countries. We draw upon existing debates on the role of RCTs in policy-making to derive a list of points of attention. We then consider four specific examples of evaluation questions for the CAP, and based on examples drawn from agricultural and social policies in developing and developed countries, argue that the RCT toolbox has the potential to significantly add to existing approaches to evaluating and designing components of the CAP.