Reading and understanding original research articles by undergraduate students in Chemistry can provide greater capacity in developing criticisms and establishing relations between scientific contents. Despite being such a relevant skill, research on the subject is scarce, especially in Brazil. In this perspective, this paper aims to investigate the understanding of original research articles on the topic of biofuel, taken from the Química Nova journal, by undergraduate students in the area, in the context of a scientific communication course. To this end, retextualization carried out by three groups of students (G1, G2 and G3, totalizing 30 students) of an original research article for a corresponding oral presentation was initially analyzed, and then relations between this process and textual understanding were established.The investigation was based on studies on retextualization operations and horizons of textual comprehension, proposed by Marcuschi. It was found that the groups used all the retextualization operations reported in this dissertation on the slides, as well as showing all horizons of textual comprehension. Thus, different types of operations, having different purposes, as well as understandings in the most varied degrees of complexity were used.Considering this, it was found that textual understanding in the minimum horizon was the most recurrent on the slides of the three groups, a fact that is possibly associated with the students' fear of making mistakes. Textual comprehension in the maximum horizon was also one of the most recurrent, showing the performance of activities of a high cognitive level. The results indicated that there was no comprehension of the totality of the original research articles by the students, however, in some moments, operations were used that indicated considerable understanding of them. As a result, it can be concluded that making the slides that comprise the oral presentation mostly occurred without affecting the communicative purpose established by the authors of the articles. In addition, the work contributes to the expansion of studies that provide theoretical and methodological support that can reshape teaching-learning activities developed in undergraduate chemistry courses, aiming to foster skills related to reading and understanding original research articles.