This paper examines the similarities and differences of the legal discourses on the prohibition of retroactive laws within the European human rights framework, and more broadly, a temporal framework that accompanies questions of historical injustice. The paper considers the significance of the notion of retrospective justice in post-1989 Europe, and more specifically in Germany and Poland. From a criminal law perspective the idea of punishing people for an act that was not a crime at the time of commission is regarded as reprehensible. However, a different temporal narrative was evoked with the fall of Communism in 1989 that was based on responses to atrocities committed during the Second World War. The paper outlines the legal context that frames retrospective justice, nationally and regionally, and considers the importance of permitting the law to work retroactively. By examining certain aspects of the German and Polish experiences, the paper concurs that retrospective justice in post-Communist Europe contributes a specific set of problems to the field of transitional justice, none of which sit comfortably with one solution, and all of which demonstrate that narratives on select chapters of Communist histories remain unfinished. The narratives also show that transitional criminal justice has taken on a permanent character in legal discourses, in which retrospective justice takes on a dynamic meaning.