In this contribution I put forward the argument that (1) the application of the adjudicative principle of ‘procedural autonomy’ leads to the creation of a European judge-made procedural law. Further, this procedural law exhibits (2) a potentially problematic trans-substantive tendency, as well as (3) a conceptual difficulty as it is applied regardless of a procedural/substance distinction, exemplified, for example, in its treatment of damages. There is therefore the need for a mechanism of differentiation in the application of the principle of ‘procedural autonomy’, which at the same time articulates procedural justice concerns.