SUMMARY
This article presents a model for analysing how probability is treated in Chilean textbooks in primary education. In order to do this, we have used theoretical tools from the Onto-semiotic Approach to Mathematical Knowledge and Instruction which have enabled us to identity mathematical objects (problematical situations, language and concepts) associated with the study of probability. These objects are analysed according to the diversity of their meanings, based on the official Chilean curriculum. The results show that probability is treated mainly from an intuitive perspective, with frequency and classical meanings then being included gradually, and with a rather superficial approach to subjective meaning.