Since the appearance of Swales' (1990) CARS model to describe the rhetorical organization of research articles, several researchers have proposed different rhetorical structures for each of the canonical sections of this genre in different disciplines. However, little research has been conducted on the structural organisation of the discussion section from a contrastive perspective. This paper, therefore, reports on the rhetorical organization of the discussion section of English and Spanish research articles in the field of Psychology using Swales' (1981, 1990) model of analysis. Even though the general results reveal that there are similarities between English and Spanish discussions in terms of the use of moves, some differences were also noted. The analysis of the English corpus showed that Providing background information, Stating results, Referring to previous research and Providing explanations were obligatory moves, while the analysis of the Spanish corpus revealed that only two moves could be considered obligatory: Stating results and Referring to previous research. Based on these findings, a single-level move structure consisting of eight moves is proposed for the articles in the corpora. The sequence of identified moves can be useful to native and non-native writers and may enhance the design of ESP course materials.