The purpose of this study was to investigate the effects of mathematical modeling activities on students' ability to transfer the mathematical concepts into daily life. The study was applied to 116 sixth and seventh grade students from one public school. The "Daily Life Mathematics Test" (DLMT) developed by the researcher was administered to both experimental and control groups as a pre-test. Activities about mathematical modeling were given to the experimental group. DLMT was administered to the students as a post-test at the end of the semester. Furthermore, as qualitative data, semi-structured interviews were carried out with the students from experimental group. The results revealed that mathematical modeling-based instruction for both sixth and seventh grade had a significant effect on students' ability about transferring mathematics into daily life compared to other groups in which the mathematical modeling-based instruction was not utilized. As a result of examining the video records obtained during the activities and interviews, it is observed that this effect might be related to properties which are naturally contained in the structure of modeling activities. Because, these activities are taken from real life and socially powerful and usually require to use metacognitive thinking skills.