The article considers approaches and methods for determining and evaluating the economic effectiveness of final stages of the life cycle of nuclear energy facilities, including nuclear legacy sites in the Arctic and on the continental part of Russia, taking into account social and environmental factors. The author proposes a relevant method based on estimates of the damage prevented, the facility disposal costs and related social indicators – the location of the facility with regard to the areas of population residence and specially protected natural sites, the availability of a credible operating organization and accessible open information support. Using the example of seven (7) disposed facilities of different types, the author evaluates economic efficiency in accordance with the proposed approaches, which allow clarifying the assessment of activities on eliminating nuclear legacy in the Arctic and the continental part in terms of their social significance and perception. The economic efficiency assessments obtained on the basis of the proposed method can be used when planning further steps to bring the nuclear legacy sites in the Arctic and continental Russia into an environmentally safe state.