This study aims to evaluate the effectiveness of in-service courses conducted by the Ministry of National Education in order to inform teachers about the changes introduced by the new primary and secondary school curricula. The study also aims to reveal whether these changes have entered the classrooms based on the teachers' views of the INSET courses they attended. For this purpose, semi-structured interviews were conducted with both primary and secondary school teachers during the 2007-2008 academic year. Data were analysed based on the effective INSET criteria identified from the literature. According to the findings, the INSET courses were found to be ineffective, mainly in terms of the quality of the instructors, teaching methods employed, duration of the courses and support after training. Suggestions to conduct effective INSET courses, especially when change is afoot, are included at the end of this paper.