Purpose of this study was to explore the effects of using the Argumentation Based Inquiry (ABI) approach (adopted from the Science Writing Heuristic-SWH approach) on students' learning chemistry subjects in the primary school. Quasi-experimental, pre-posttest design was applied. The study involved two 8th grade classes of one teacher from a primary school in a disadvantaged social economic area of Erzurum. While one of the randomly selected section, the treatment group, engaged in argumentation based inquiry activities by using the ABI approach and students wrote activity report for each activity individually, the other section, the control group, instructed with usual approach used by the instructor in the previous semesters. The study was implemented in the properties and structures of matter unit. As data collection tools, chemistry subject based tests (9 multiple choice questions and 4 open-ended questions) were developed and used as pre and post assessments. The pre-posttest was generated by using national and international question banks. Analysis of the tests indicated that groups were not statistically different at the pre-test but statistically different at the post-test. The treatment group outperformed the control group and students' writing score correlated with post-test score. Also, there was a significant correlation between test scores and students' reports generated during the activities.