This study investigated the effect of problem posing on the pre-service primary teachers' understanding of fraction concepts enrolled in two different versions of a methods course at a university in Turkey. In the experimental version, problem posing was used as a teaching strategy. At the beginning of the study, the pre-service teachers' knowledge of symbols and algorithms was adequate in both groups, but they were unable to provide appropriate representations and explanations for the given fraction situations. Results showed that problem posing had a positive impact on the pre-service teachers' knowledge and views about what it means to know mathematics. (Contains 9 tables.)