Fear of overpopulation and underpopulation is not a new issue. Regularly, it reappears in the discussion of scientists in particular of demographists and ecologists. This article presents a brief review of mainly Anglo-Saxon studies highlighting the apocalyptic dimension of demographic thought. It emphasizes the arguments used trough the presentation of a number of discourses that are based on demographic concepts and parameters and on their impacts on the future of humanity, regions or states. It underlines in particular the narrative force of apocalyptic representations, although secularized, through the usage of scientific arguments and quantitative studies which built catastrophic scenarios whose occurrence is always postponed.