The aim of this study was to examine the change of ELT pre-service teachers' cognition during teaching practicum uncovering their beliefs regarding language teaching, being a teacher and dynamics of practicum. To adopt a comprehensive perspective on how the participants? cognition evolved as a result of practicum, qualitative research design with open-ended surveys before and after the practicum process was conducted with ELT pre-service teachers. The findings were evaluated and discussed in terms of a certain framework with change categories of Cabaroglu and Roberts (2000). The results indicated that the practicum is apt to change the pre-service teachers' beliefs through "awareness," "elaboration," "addition," "re-ordering" and "reversal" as a result of practicum. As the results suggest the practicum provides a real-life context for the pre-service teachers, they could adopt their grounded beliefs, which were acquired as language learners, and transform them into language teachers' beliefs. As the participants stated the mentor, supervisor and classroom dynamics enabled such transformation, mostly in positive route. However, there are some stable beliefs that did not change during the practicum. The participants kept some "functioning" beliefs for their teaching practice. The results implied the complexities of the practicum process on the pre-service teachers' cognition.