This study aims to analyze the modalities in the scientific paper genre of Linguistics field, the functions they perform as markers of speaker's attitudes and the relationship of these modalities with the argumentation in this text genre. Our hypothesis is that in scientific papers, modalities have functions related to the argumentation. In this research, a theoretical study of text and discourse was done according to Bakhtin (1997) and Travaglia (1991), then the argumentative structure of this genre was investigated, taking as theoretical basis Perelman and Olbrechts-Tyteca (2002). The qualitative methodology has been used to focus on linguistic and social aspects of the scientific paper genre of Linguistics field. In this study, it was found that in order to have the support of the reader, the authors use the epistemic modalities throughout the construction of the text. However, it was observed that this kind of modality has taken different functions for each part of the text superstructure, while the volitional modality appears only in the introduction and at the end of the conclusion to mark intentions and pretensions. Also, it was noted that in scientific papers the most commonly used modalities are the epistemic, deontic and alethic, while the volitional and imperative modalities are less used.