We will discuss how to determine the truth value of categorical propositions in Aristotelian logic, where, our focus is on the existential import in categorical propositions in this article. A proposition is accepted to have existential import, provided that the truth of this proposition requires a belief in the existence of members of the subject class. The fact that, the correspondence of the proposition, in reality, is related to the existence of terms in the proposition raises the question of which propositions need an existential assumption to be true in traditional logic. The existential import in Aristotelian logic has been severely criticized on two issues: (i) How to determine the truth value of propositions when non-referential terms are the subject of the proposition? (ii) Is the contradiction between the categorical propositions partaking the square of opposition reliable? By considering these two questions, we will examine whether categorical propositions containing existential import cause inconsistency or not in Aristotelian logic.