This dissertation describes and analyzes the characteristics of the case report genre found in biomedical periodicals. This genre has aroused considerable discussion in the medical community, concerning the value and the representativeness that this kind of text has for medical publications. As background to the discussion, this study outlines work in the area of language and science and, as well, the issues of editorial policy in contemporary scientific publications. The central concepts from genre theory that underlie this research are the ideas that a genre is typified rhetorical action, it is constructed within a discourse community, and it fulfills/meets a particular communicative purpose (Bazerman, 1988, 2004; Bhatia, 1996; Miller, 1984; Swales, 1990).The analysis uses an adapted version of Swales (1990, 2004) CARS model, to show the rhetorical pattern of information in the case report and the characteristics that identify it as a genre. The analysis also extends to the function of the titles and to the semiotic system of images, in addition to the linguistic system, in the construction of meaning in the text. The model that emerged from the analysis, with three rhetorical movements and eleven sub functions, reveals that the case report is a hybrid genre with traits of the report and the research article. Thus, the study suggests that this genre has its own place as a kind of academic text and that it serves a particular purpose for the medical community.