Teachers' content knowledge impacts on what they teach, how they teach and what their students learn. In order to check whether the prospective teachers in a rural South African university know the mathematics content they are expected to teach in the schools, at least at the same depth as their future students expected to attain, the research on the Student-Level Disciplinary Content Knowledge (SLDCK) of a sample of 40 Bachelor of Education (Mathematics) students was conducted. The theoretical framework rests on theories on subject content knowledge of pre-service teachers. The data were generated from the performance of the prospective teachers in two tests on the selected topics in the South African senior secondary school mathematics curriculum and also from document analysis. It was found that the prospective teachers had only limited SLDCK on the topics that they were meant to teach in the schools. An in-depth analysis of the course modules offered at the university also revealed that the prospective teachers' limited SLDCK was due to the curriculum constraints of the university. Effective teaching measures to close the gap in the SLDCK and changes in the teacher training curriculum of the university are recommended to enhance the preparation of prospective teachers of the country.