Unlike western languages such as English and French, there has little literature on Korean existential sentence. It comes from two factors: Frist, Korean does not have any existential construction exclusively definable from a syntactic point of view. Second, Korean lacks a clear category of definiteness like articles. But I argue that Korean also has its own existential construction. It is supported by the fact that although a certain sentence can be used as either existential or non-existential with no morpho-syntactic changes, there is no misunderstanding between interlocutors on which is an existential sentence. Those differences between Korean and English make us examine Korean existential sentences with different methods from English. I start with the syntactic structure of ‘Locative + Noun Phrase + Existence Verb’ for Korean existential construction, and investigate four types of Noun Phrases because the Noun Phrase part is the most important in discussing Korean existentials. Then we obtain two important properties. First, the nominative case marker is a necessary element for existential sentences. Second, phonological focus plays a crucial role in determining existential sentences when the Noun Phrase consists only of noun. That is, H is assigned to the bare Noun Phrase only when it is an argument of ordinary existentials. In order to accommodate the phonological focus effect, I use Jun’s(1993) proposal that focused word initiates a new Accentual Phrase which covers all of the following unfocused material up to the next likely Intonational Phrase boundary. Finally I propose the following construction for Korean ordinary existential sentences: Locative {NP-Nom V$sub$EXIST/} where {. . .} means one Accentual Phrase On the other hand, following Abbott(1992/1993), I distinguish between ordinary existentials and contextualized existentials. The latter requires a special context and carries more information than asserting the existence of an entity.