The aim of this study was to increase understanding of how to change theoretical and practical knowledge of primary school teachers. The research approach was qualitative. The data were collected through focus group interviews. The sample size was obtained after the saturation phase including 25 teachers. The data were analyzed using content /thematic analysis. Two techniques were used for increasing the trustworthiness of data including member check, and peer review or debriefing. The findings were labeled in three categories comprising the quality of theoretical and practical knowledge change, the change channels of theoretical and practical knowledge of teachers and the factors influencing the change of teachers' theoretical and practical knowledge. These categories embraced the sub-categories. As sum, the results revealed that the low quality of teachers' in-service curriculum bring the unimportant change in theoretical and practical knowledge of teachers. Design and development of teachers' in-service curriculum, needs change in instrumental perspective of designers and executives of curriculum-making toward change phenomenon in teachers.