Formally specifying hedonic well-being is difficult, but relevant to utilitarian theories of morality. In this paper we describe a starting point based on attitudinal hedonism, which posits that hedonic well-being is determined by the extent to which a moral patient believes her preferences to be fulfilled. While this assumption probably does not capture the sought-out notion of well-being fully, our formalization seems to be relevant first step towards more satisfactory definition of hedonic well-being.