The abstract has become a fundamental genre in the academy due to its role in the dissemination of scientific knowledge. For this reason, it is important to describe this genre in the context of different disciplines. This article describes the rhetorical variation in medicine and linguistics as well as the way in which the information is evaluated in these disciplines. To do this, Hyland's (moo) proposal for rhetorical organization and Martin and White's (2005) appraisal theory are used. The results show that the organizations P-P-Pr and P-M-Pr-C are the most frequent in both disciplines, although in linguistics the moves of introduction and conclusion are less common. Both disciplines privilege appreciation in the introduction and product moves. Medicine, in particular, shows a trend to display appreciation in the conclusion move. These findings help account for variation in a novel manner considering not only rhetorical organization but also evaluation.