The aim of this study is to investigate the effect of research-inquiry-based learning approach on the Scientific Reasoning Skills of Science Education Prospective Teachers in the Nature of Science and Science History Course. The study was designed as a single group pre-test -- post-test model. The study group consisted of 31 prospective teachers in the 3rd grade of Science Education program in a public university in the spring term of 2017-2018 academic year. For the scientific reasoning skills of prospective teachers "Scientific Reasoning Skills Test - SRST" was measured as a pre-test, then the Nature of Science and Science History course was conducted with the Research-Inquiry Based Learning Approach and SRST was applied as a final test. This test consists of 7 sub-dimensions and contains a total of 26 items. The findings of the sub-problems of the study can be expressed as follows; a significant difference was found between the SRST pre-test total scores and post-test total scores in favor of the post-test total scores according to the sub-dimensions of proportional thinking, correlative thinking and hypothetical thinking. There was no significant difference in the post-test total scores according to the sub-dimensions of conservation laws, identifying and controlling variables, combinatorial thinking and probabilistic thinking. There was no significant difference between SRST pre-test and post-test total scores of man and woman students. A significant difference was found only in the sub-dimension of combinatorial thinking in the total scores of the sub-dimensions of SRST.