Curriculum fidelity refers to the closeness between the formal and implemented program and is the determination of how well a curriculum is implemented in line with its original design. The teacher is emphasized as an important variable for curriculum fidelity, and his/her attitudes and behaviors during the implementation of designed curriculum are important for the innovation and development studies in curriculum and instruction field. In this context, the aim of this study is to reveal the curriculum fidelity behaviors of primary teachers who are to use curriculum of different disciplines. This study was based on a survey design in which quantitative data were used. In this context, the Curriculum Fidelity Scale and an open-ended questionnaire form were applied to a total of 516 primary teachers who voluntarily participated in the study. The data obtained were analyzed with descriptive statistics, t-test, one-way ANOVA tests. The findings showed that primary teachers have a high curriculum fidelity highlighting the programs' functions of directing the learning activities and informing about the targets of the school subjects. In addition, it was concluded that while the primary teachers felt the need to apply to curriculum of the core subjects, they mostly benefited from the curriculum components which are learning and teaching activities. [This article includes an extended summary in Turkish.]