The purpose of this study is to evaluate the instruction program of preparatory classes at Yildiz Technical University using CIPP model. A total of 54 teachers and 753 university students attending preparatory classes in the Academic Year of 2014-2015 formed the study group. The research is based on a questionnaire applied to teachers and students. For the analysis of the data, the means and the standard deviation scores were determined separately. Furthermore, in order to figure out the differences between teachers' and students' responses, independent samples t-test technique was applied. The findings have indicated that although the teachers and students have some apprehensions on a few items such as balancing of skills, lacking of audio-visual materials, not acquiring the habit of studying in groups and the knowledge of English for different areas, they generally hold positive ideas towards the curriculum. It has also been revealed from the responses that, except for the context factor of the instruction program, the difference between the teachers' and students' opinions about the other factors of the instruction program are not significant.