This thesis explores the concept of dematerialization, which was introduced by Lucy Lippard and John Chandler to art context, by the means of a new characterization of word-based Conceptual artworks as types. Concerning the notion of dematerialization, it is argued that the notion itself is controversial and vague. In order to clarify the notion of dematerialization, a distinction between art-work and art object, which is dematerialized, is executed. Following this distinction, it is claimed that in the context of Conceptual art, the notion of artwork is more proper than the notion of art object. In this respect, art object is taken as the final product or a part of the artwork. Via taking the dematerialization process as a negation of artwork as object qua end product; ephemeral or transient character of Conceptual works; use of words as artistic material into consideration, it is argued that Conceptual artworks are types. It is argued that use of words in Conceptual art is one of the main conditions reinforcing the dematerialization process which can be seen in almost every example of word-based Conceptual artworks. Through this characterization of Conceptual artworks as types, notion of dematerialization is clarified. Finally, it is argued that as the art object dematerializes; in word-based Conceptual artworks, the place of dematerialized art object is replaced by the use of words.