The aim of this study is to evaluate the effects of Argumentation Based Science Teaching on 5th grade students' conceptual understanding of the subjects related to "Matter and Change". This research is a qualitative research and its design is a multiple (compare) case study. In this study, semi-structured interviews related to the concepts were conducted before and after the experimental period in order to assess students' conceptual understanding. The result of the study showed that students who have been trained with argumentation-based science teaching approach showed progress in conceptual understanding. In addition, it has been observed that students were able to explain these concepts with correct warrants and connect them with everyday life.