The University of Costa Rica seeks to prepare students for understanding academic texts in English by requiring reading comprehension courses in numerous degree programs. In this context, this paper aimed to assess the effectiveness of graphic organizers as a strategy to promote reading comprehension by focusing on the identification of rhetorical functions in argumentative texts. The paper followed an explanatory-sequential design within a mixed-methods approach with a group of 20 students at the Western Branch of UCR. To apply the strategy, three argumentative texts and their corresponding graphic organizers were used. The data consisted of performance scores and of answers to questionnaires. After the cycle of applications, the results showed a gradual improvement in the identification of rhetorical functions, particularly of arguments and counterarguments. Support for the authors arguments, rebuttals to counterarguments, and the authors overall claim were slightly more difficult to identify. The participants found graphic organizers helpful to better understand the parts of an argument in a text and its overall organization. At the same time, they found that the lack of explicit discourse markers and of familiarity with the content made understanding the connections between rhetorical functions difficult in spite of the help provided by the organizers. The study concluded that repeated implementation of graphic organizers has a positive impact on reading comprehension by helping students to read more strategically. However, accompanying strategies such as summarizing and discriminating main ideas from supporting details are necessary to complement the work with graphic organizers and improve their effectiveness.