The aim of this study is to reveal how engineering design-oriented science activities cause a change in middle school students' profession preferences and perceptions. As a research method, illustrative case study method was adopted to obtain more detailed and explanatory information about the purpose of the study. The study group consists of three science teachers and their students who have received STEM education using the criterion sampling method, which is one of the purposeful sampling types. In the study, the developed engineering design activities were applied by three science teachers in their classes for 9 weeks. As a data collection tool, the Profession Free Drawing Test, which provides both visual and written data, was used to determine students' profession preferences and perceptions. According to the findings, while the profession preferences of middle school students were against non-STEM professions such as doctor, nurse and police before the application, the majority of them changed as STEM professions such as engineers, architects and scientists after the application. In addition, while students had perceptions of professions such as earning money, entertainment, vacation before the application, this perception changed as problem solving, design and development after the application. On the other hand, considering that family influence is an important factor in children's profession selection, it is thought that participation of families in such design activities will contribute to the STEM professional development of children.