This study investigates 2-5-year-old Mandarin-speaking children's interpretation of the disjunction word huozhe ('or') in two positions in ruguo ('if')-conditional statements, i.e., in the antecedent clause versus in the consequent clause. The findings from three experiments show that the meanings children assign to disjunction and to ruguo-conditionals conform closely to the meanings that are assigned to the corresponding logical connectives in classical logic. Experiment 1 demonstrates that children assign an inclusive-or interpretation to disjunction in both the antecedent clause and in the consequent clause of conditional statements, whereas adults assign an exclusive-or interpretation to disjunction when it appears in the consequent clause of conditional statements. The findings of Experiment 2 provide evidence of children's adherence to a putative semantic universal-that disjunction licenses a conjunctive entailment in the antecedent clause of conditional statements, but not in the consequent clause. It is shown in Experiment 3, moreover, that children's knowledge doesn't stem from their mistaking disjunction as conjunction. Because the logical meanings of connectives emerge early in the course of language acquisition, and without decisive evidence from the adult input, these findings suggest that children draw upon an innate logical vocabulary at the initial stages of language acquisition.