Abstract
With the enactment of the Lisbon Treaty, EU law gained supremacy over national law in ten areas of criminal law (with the possibility of extension in the future) treated as particularly serious crimes with a cross-border dimension and the right to enact directives. The question arises if and when direct effect is possible in criminal law, taking account of developments and applications of this principle in other areas of EU law. To answer this question, the following tasks are necessary: (1) to discuss the role of principles in criminal law, (2) to define the principle of direct effect through the academic literature and the jurisprudence of the CJEU, (3) to discuss whether directives could have direct effect in criminal law, and (4) to analyze the EU’s impact on Lithuanian national criminal law through an analysis of the jurisprudence of the Supreme Court of Lithuania.