During the last decades, we have seen that, next to an internationalization of crime, an increasing internationalization of criminal justice has taken place. Evidentially, this is true for different levels of criminal justice, but in this paper we will focus on the international execution of sentences. The internationalization of criminal justice brings new experiences for penology, which had traditionally been linked to a national (domestic) framework. The central focus of this paper will therefore be the relationship between international and national execution of sentences. Three research questions will be dealt with: (i)Which historical processes have driven international execution of sentences?; (ii) What are the basic principles of international execution of sentences? Which compromises have been sought and which choices have been made?; (iii) Taking into account the motivational processes underlying the rise of international execution of sentences, and the differences and similarities that exist with domestic execution of sentences, what could/should be the role and/or function of this relatively new instrument? Does international execution of sentences have an added value, and if so, in which respect?