The aim of this study was to determine effect of inquiry based learning method on the instructional materials motivation of prospective chemistry teachers' in chemistry laboratory. A pretest-posttest control group design was used in the study. The study group was consists of 22 prospective chemistry teachers' who are undergraduate students at a University. There were 11 prospective chemistry teachers' in each of the experimental and control groups. The study was carried out in analytical chemistry laboratory. In the experimental group had been followed inquiry-based chemistry laboratory experiments. In the control group had been experienced traditional verification laboratory experiments. The instructional materials motivation survey was used as data collection tool. In terms of instructional materials motivation there was no difference between the experimental and control groups before laboratory application. After the application the results indicated that inquiry-based learning is effective in improving instructional materials motivations prospective chemistry teachers.