Understanding mathematics related belief change in teacher education programs has been a concern due to the information it presents about the effectiveness of program experiences. The present study investigated how preservice mathematics teachers' (PMTs) mathematics related beliefs changed through a teacher education program by implementing a belief scale to a cohort of PMTs 12 times during 6 consecutive semesters. Comparison of mean scores for different time periods showed that the cumulative effect of the teacher education program is more detectable than year-long or semester-long effects. While such implementation is likely to provide a perspective for monitoring belief change and possible effects of courses, it might also address that the contents of the courses should be connected to ensure the best cumulative effect of the programs.