While both Finland and France are seen as forerunners in final disposal of nuclear waste, there are striking differences between the countries in public and policy discussion on the safety of the project. This paper studies safety-related arguments in national-level decision-making on final disposal of nuclear waste in Finland and France, using selected parliamentary documents as the empirical material. The paper adopts safetization in decision-making on nuclear waste management as its central concept. By safetization we refer to a process whereby, first, images of risks and uncertainties are either created or explained away to give assurance of safety. Second, current practices are normalized, or various – sometimes even exceptional – measures are demanded in order to change current practices and thereby solve the issue and ensure safety. Thus, prevailing views of safety can be supported to build further trust and confidence or alternatively challenged in order to achieve more robust understanding regarding the issue. As a result of safetization, political power will be re-distributed between key actor groups such as implementers, regulators, and politicians. Our empirical analysis explores such processes whereby members of parliament frame, politicize, and depoliticize safety. We employ four data corpuses, two from both case-study countries. The Finnish data consist of the minutes of two plenary sessions of the Finnish Parliament. The first, held in 2001, concerned the Council of State Decision-in-Principle on Posiva's application for the construction of a spent nuclear fuel disposal facility, whereas the second, in 2015, discussed the Statement by the Prime Minister on Nuclear Waste Management Research and Safety Assessment. The French data consist of the debates in preparation for two specific acts on nuclear waste: the first (from 2006) on the framework law on the management of radioactive material and waste and the second (from 2016) on the law defining the conditions for the creation of a reversible deep geological facility for high-level waste (HLW) disposal. The focus of the analysis is on the identification of frames and four frame functions. The functions are as follows. (1) Definition of a situation, issue, or problem related to final disposal. (2) Diagnosis of causes or reasons for the situation as it is portrayed in the data or in a speech. (3) Evaluation or judgement concerning the situation and possibly the actors involved. (4) Suggested course of action. We argue that safety is not only an outcome of scientific research and technical competence, but that efforts to ensure safety also include framing of safetization and de-safetization in political and public debate. Research on energy policy should integrate safetization as a key topic alongside issues such as energy security and climate change mitigation, given that safetization involves similar politicization and de-politicization processes and the exercise of power.