Dongseok Kim & Yong-Ha Kim. 1999. Cost of Merge and Move. Studies in Modern Grammar 17, 33-66. In this paper we argue against Chomsky`s (1995, 1998) assumption that Merge preempts Move, and claim that Merge and Move have the same status with respect to economy. We assume, following Collins (1997), that Merge involves copy and Merge just like Move, and the unique difference is that Move involves copying an already introduced element, whereas Merge involves copying a new element from the lexicon. Under this assumption, Numeration is unnecessary and Procrastinate is eliminated in favor of local economy. On the basis of Object Shift and multiple specifier constructions in Korean, we have shown that Merge as well as Move apply as Last Resort, and that whether to apply Merge or Move is contingent on the properties of the features that must be satisfied at each stage of a derivation. As a principle to decide between them, we have proposed Narrow Domain Principle and proved it successfully works on a wide range of relevant constructions.