The German Code of Crimes Against International Law can be considered a ‘well-crafted’ law. It has not only been put to test in practice in several high-profile cases before German Higher Regional Courts, but it also serves as a model for the implementation of international criminal law into domestic legislation. Nevertheless, 20 years after its entry into force and from a point of view of substantive law, it is possible to identify areas of the Code that are in need of legislative reform, such as sexual and reproductive crimes, crimes against the environment, the crime of aggression, war crimes against property and the applicable sentencing ranges. This article provides an overview of these areas and discusses possible ways forward.