Presupposition and Intension. ln this paper, I argue for the adequacy of formal approaches to the description of meaning, even in cases of expressions conveying conventionaI implicature. By formal approaches, I mean frameworks intended to account for sentence meaning, and meeting the conditions of compositionnality, autonomy towards knowledge and beliefs about the world, and modularity. I first show that presupposition, instead of being considered as a relation between a sentence (or an utterance) and another sentence (or, at best, a proposition), should rather be seen as a relation between a sentence and a meaning. Besides avoiding the presupposition-entailment paradox, this position is shown to allow a compositionnal treatment of presupposition, using, for instance, Karttunen and Peters' tools. 1 then give the bases of a «representation al semantics», that aims at freeing semantic description from both speakers» intentions and truth conditions. 1 conclude with a couple of examples of semantic analyses for sentences containing intensional verbs such as «savoir» or «espérer», and show how these analyses fulfill the task they were ascribed. Some questions are left open as to the generalization of this treatment to other intensional cases, and as to the exact shape meaning representations should have.