This study aims to analyze doctoral dissertation abstracts written by American writers and Korean writers from the standpoint of contrastive rhetoric. We selected five doctoral dissertation abstracts by American writers and five doctoral dissertation abstracts by Koran writers, using the authentic internet site. Based on the IMRD structure suggested by Swales (1990), we tried to analyze their macro-structure. The Micro-structure of our material was analyzed, based on the cases of passive voice usages claimed by Greenbaum (1990) and some referential expressions such as ``the, this, etc.`` We could not find a meaningful difference of their macro-structure. Abstracts by Korean writers are much longer than those of American writers. The reasons for the use of passive voice are different. American writers use passive voice for cohesion, whereas Korean writers use it for objectivity. Concerning referential expressions, it was interesting that both writers use ``this, these`` more than ``that, those``. It seems that writers feel their dissertation psychologically near. In this investigative research, we suggest Korean writers write abstracts more briefly and concisely to attract readers.