The repugnant conclusion can be formulated as follows: For any population consisting of people with very high positive welfare, there is a better population in which everyone has a very low positive welfare, other things being equal. As the name indicates, this conclusion appears unacceptable. Yet it has proven to be surprisingly difficult to find a theory that avoids it without implying other very counterintuitive conclusions. Moreover, the conclusion is a problem not just for total utilitarians or those committed to welfarism but for all moral theories according to which welfare matters at least when all other things are equal, which arguably is a minimal adequacy condition for any moral theory. And, not the least, how to deal with it has implications for the present generations’ duties to future generations and intergenerational justice. The question as to how the repugnant conclusion should be dealt with has thus become one of the cardinal challenges of modern ethics, and the inquiry into what it shows about the nature of ethics has opened up many new avenues for research. This chapter covers the different suggestions in the literature on how to do deal with the conclusion, both on the axiological and on the normative levels. Moreover, the conclusion and different ways of deriving it are explained in detail.