This study was conducted to reveal teachers' views of the effectiveness of the INSET courses they attended on the new curriculum and to evaluate the courses based on the teachers' views and the effective INSET characteristics reported in the literature.The participants were 20 primary and 18 secondary school teachers. 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. The authors conclude with suggestions to conduct effective INSET courses.