The aim of this paper is to show that it's not a good idea to have a theory of truth that is consistent but ω-inconsistent. In order to bring out this point, it is useful to consider a particular case: Yablo's Paradox. In theories of truth without standard models, the introduction of the truth-predicate to a first order theory does not maintain the standard ontology. Firstly, I exhibit some conceptual problems that follow from so introducing it. Secondly, I show that in second order theories with standard semantics the same procedure yields a theory that doesn't have models. So, while having an ω-inconsistent theory is a bad thing, having an unsatisfiable theory of truth is actually worse. This casts doubts on whether the predicate in question is, after all, a truthpredicate for that language. Finally, I present some alternatives to prove an inconsistency adding plausible principles to certain theories of truth.The initial formulation of Yablo's Paradox 1 consists in an infinite set of sentences that is linearly ordered. Each of them claims that all sentences occurring later in the series are not true. At least at a superficial level, the series doesn't seem to involve any kind of self-reference. 2 According to Yablo, the set of sentences would be incapable of having a model and, therefore, it would be unsatisfiable. Of course, this result is controversial. It has been criticized by Priest and Ketland. 3 In particular, starting from a formulation of the series expressed in the language of arithmetic, Ketland shows that it is possible to find a non-standard model for Yablo's sequences. In this paper, I argue that Yablo's sequences introduces new boundaries 1 [23] and [25]. 2 Far from a general consensus on this, there are many who claim that Yablo didn't manage to show that there is not some kind of circularity involved in his sequence. Mainly, Priest and Beall belong to this group and Bueno, Colyvan, Leitgeb, Sorensen and Yablo have maintain that Yablo's list generates a semantic paradox without circularity. See [1, 2, 13, 16, 20] and [25]. 3 See [16] and [11].