Population ageing and the global burden of dementia pose a major challenge for human societies and a priority for public health. Cognitive enhancement, i.e. the targeted amplification of core cognitive abilities, is raising increasing attention among researchers as an effective strategy to complement traditional therapeutic and assistive approaches, and reduce the impact of age-related cognitive disability. In this paper, we discuss the possible applicability of cognitive enhancement for public health purposes to mitigate the burden of population ageing and dementia. After discussing the promises and challenges associated with enhancing ageing citizens and people with cognitive disabilities, we argue that global societies have a moral obligation to consider the careful use of cognitive enhancement technologies as a possible strategy to improve individual and public health. In addition, we address a few primary normative issues and possible objections that could arise from the implementation of public health-oriented cognitive enhancement technologies.