The aim of this study was to examine mathematics teachers' concerns about the sixth grade curriculum that was launched in Turkey in 2006. As a data collection tool, the Stages of Concern Questionnaire (SoCQ), based on the Concerns Based Adoption Model (CBAM), was administered twice (at the beginning and the end of the instructional year) to 110 teachers who were using the new mathematics curriculum for the first time. The same teachers were also asked to provide an open-ended statement in order to obtain qualitative data. The data were analyzed separately to highlight changes in the teachers' concerns about the 6th grade curriculum. According to the results, the teachers were mainly concerned about becoming sufficiently informed about the program; organization and timing issues; inadequate school conditions and students' backgrounds. They were also concerned about the new instructional materials, although the intensity of their concerns changed over time.