The aim of the study is to determine the causes of anxiety in mathematics lessons and during which periods this anxiety occurs. This study has been conducted through using mixed method, in which qualitative and quantitative data are collected and analyzed together. The study group consists of 156 students, who are 2nd, 3rd3 and 4th graders studying at the department of Classroom Teaching of the Faculty of Education in Ondokuz Mayıs University. The data collection tools of the research are the ‘’Interview Form for Anxiety in Mathematics’’, which was developed by researchers, and thr ‘’Mathematics Anxiety Scale’’, which was developed by Biber (2012). Qualitative data were analyzed through content analysis method, whereas quantitative data were analyzed through t-test. The results suggest that the anxiety level of students is not significant based on what grade they are; however the interviews indicate that primary school teachers are closely associated with the anxiety level of students. Moreover, it was also found out that the attitude of the teacher influences students’ lives and teaching methods directly affect students’ attitude towards mathematics.