This paper investigates the code-switching of personal pronouns in the speech of Vietnamese-English bilinguals in Melbourne. The highly complex system of person reference in Vietnamese has no counterparts in the English speaking world, and is examined in this paper. Relying on Myers-Scotton's Markedness Model (1993), I discuss in some detail the code-switching of English personal pronouns and argue that the switching of personal pronouns is to signal a change in the relationship between the addressor and the addressee.