This study aims to reveal the mathematical reasoning process of 8th-grade students and the reasoning indicators they use in this process. The study was carried out in line with the data obtained from the Mathematical Reasoning Test (MRT) administered to 292 8th-grade students. The mathematical reasoning performances of the participants were generally at low and medium levels. Evidence was found that students used reasoning indicators such as "… for/because of…, /therefore/so/thus…", "if … then…", "because…", "should be/should be..." and "equal..." when reasoning. It is important that when evaluating the solutions to questions that require mathematical reasoning, students must be interviewed and confirmed how they reached those solutions. The limitations of the research are, firstly, that it is limited to 8th graders, and secondly, that students will get bored if the number of questions in the MRT is high. Students must be asked to justify their reasoning while solving problems that require mathematical reasoning.