According to Longtermism, our acts’ expected influence on the expected value of the world is mainly determined by their effects in the far future. There is, given total utilitarianism, a straightforward argument for Longtermism due to the enormous number of people that might exist in the future, but this argument does not work on person-affecting views. In this paper, we will argue that these views might also lead to Longtermism if Prudential Longtermism is true. Prudential Longtermism holds for a person (...) if and only if our acts’ overall influence on that person’s expected well-being is mainly determined by the acts’ effects in the far future. We argue that (due to a small chance of anti-ageing and uploading) there could be an enormous amount of prudential value for some contemporary person in the far future and that value may be so large that it dominates their overall expectation of lifetime well-being. (shrink)