Objective. Describe and analyze the conceptual change in the mental representation structure construed by a group of readers during the comprehension of a narrative text. Method. A qualitative study with verbal analysis methodology was carried out with 13 fifth grade primary school students. Three reading sessions were held using the same narrative text with the aim of comparing their performance. Three measurements were taken in each session with the task of free verbal production; at the same time, intra-session and intersession measurements of performances were compared. Results. The results show that the conceptual change during comprehension presents different tendencies with regard to the different structural properties of the mental representation which are examined. Conclusions. The findings contribute to the understanding of the dynamics in the mental representations during comprehension, and have some implications for the theories of comprehension and learning based on the reading of texts.