This paper aimed to describe the knowledge genres used in textbooks of five subjects in the second cycle of Chilean elementary education. Using a top-down/bottom-up approach, these genres were identified in a corpus of 100 textbooks distributed by the Chilean Ministry of Education between 2012 and 2016, and were characterized in terms of their communicative purpose, semiotic organization and discursive organization. The analysis showed that among the 15 knowledge genres identified there is a significant prevalence of those aimed at disseminating declarative knowledge. In addition, some genres occurred in only one subject, and those genres identified in all subjects varied significantly in their frequency of occurrence. These results show interesting differences among subjects in terms of the ways used to disseminate knowledge through recontextualization and resemiotization.