This article intends to highlight the concept of subsidiarity in the area of the third pillar and EU criminal law more generally. In doing so, the article tries to show that criminal law could and should be seen as imbued with 'subsidiarity'and, more specifically, that it could be viewed as an expression of the principle of ultima ratio - a minimalism approach - in criminal law. Accordingly, the article asks why subsidiarity appears to be forgotten in third pillar matters despite its important function in this area. Moreover, the article confronts such a desired application of subsidiarity in the context of established EC law doctrine, by questioning whether it is possible simply to transplant the supranational discussion into the terrain of criminal law. Further, the article explores the function of Article 47 EU as the watchdog of the supranational sphere and discusses also briefly the phenomenon of enhanced cooperation in relation to the principle of subsidiarity in the domain of EU Justice and Home Affairs. © 2009 Blackwell Publishing Ltd.