In this study, both the activities prepared by pre-service science teachers regarding the Problem Based Learning method and the pre-service science teachers' views regarding the method were examined before and after applying their activities in a real class environment. 69 pre-service science teachers studying in the 4th grade of the science education participated in the study. This study was designed as a case study. In the result of analysis, it was determined that the pre-service science teachers could develop activities using the features of the problem based learning method. However, it was concluded that pre-service science teachers faced difficulties in some phases during the activity development process such as generating scenarios related to daily life and finding problems to direct the students to inquiry. In the result of semi-structured interviews conducted with pre-service science teachers, it was determined that they had positive and negative views regarding the PBL method before and after the implementation in a real class setting.