This article closely analyses mutual recognition as a justification for EU legislative activity in the field of domestic criminal procedure. By looking at the structure, wording and purpose of the Treaties, the article first discusses the proper interpretation of the mutual recognition criterion in Article 82(2) TFEU. It argues for a narrow construction of Article 82(2) TFEU, suggesting that the expression ‘enabling mutual recognition’ is capable of substantially confining EU action on criminal procedure. The article challenges the justification for having EU competence in domestic criminal procedure on the basis that it enables mutual recognition. It advances the proposition that it is very difficult to defend on a conceptual and empirical basis that harmonisation has a positive effect on the operation on mutual recognition.