In this study, we examined changes in levels of pre service teachers' reflective writing and tried to identify links between these changes and pre service teachers' success in teaching. Participants were two groups of pre-service special education teachers that taught in two different special education settings: learning difficulties classes and multiple and profound intellectual disabilities classes. Data collection was performed during two consecutive academic semesters, including a monthly structured journal about teaching events during field experience and summative grades, assessing pre service teachers' teaching activities for each semester. Journal analysis referred to three reflective levels of explanations, descriptive, comparative and critical. Results indicated that both groups improved in descriptive levels of explanations, but only one group improved in higher levels of reflective (comparative and critical) explanations. Differences between the two groups were explained in context of different settings in field experience, lack of former knowledge and experience in one group, participants' characteristics and different supervisor's responses to the journals. These differences explain the higher levels of reflective thinking in one group. A positive correlation was found between grades in field experience and descriptive and comparative explanations in the first semester for both groups. In the second semester, field experience grades correlated only with critical explanations, meaning that only those who reached critical level of explanations also improved their teaching acts correspondently. These results point towards a professional developmental relation between reflective writing and teaching during teacher education process. (Contains 2 tables.)