This study aims to reveal prospective middle school mathematics teachers' knowledge regarding the possible misconceptions and/or errors of middle school students in describing integers. In addition to this, it aims to reveal the possible reasons underlying these from the perspective of prospective teachers. Data was qualitatively collected from 38 Turkish prospective teachers by an open-ended questionnaire. The results show that although prospective teachers are familiar with possible misconceptions and/or errors of middle school students in describing integers, each prospective teacher does not have a rich repertoire regarding students? thinking process even though it seems that there is a rich repertoire in total. They did not give sufficient details about the content and pedagogical aspects of the misconceptions and/or errors. They proposed quite general ideas about the misconceptions and/or errors and the reasons for them.