The Lisbon Treaty introduced the ability to transfer the power to adopt non-legislative acts of general application (delegated acts) and nonlegislative acts to ensure the uniform conditions for implementing legally binding Union acts (implementing acts) in a legislative act to the European Commission. Delegated and implementing acts may not change the essential elements of the legislative act. Safeguards have been included in the legislative decision-making process to prevent the European Commission from abusing its delegated and implementing powers. Nevertheless, from time to time, a case is referred to the Court of Justice of the European Union (CJEU) about the validity of these types of acts. In this contribution, the author discusses the decision-making process for them and their position in the framework of EU customs legislation. It also analyses whether the European Commission abused its delegated and implementing powers granted in the Union Customs Code (UCC) based on several examples. The author concludes that it does so in numerous cases thereby increasing uncertainties about the legality of the delegated and implementing acts of the UCC. This conclusion may also be extended to and therefore be of interest for other areas of EU (tax) law.