The aim of this paper is to provide insights into nine primary school teachers’ concerns and instructional needs in biology and mathematics, grades 1 to 6. By using Content Representation, combined with Learning Study in an action research project, teachers were encouraged to reflect on their conceptions, processes of instructing and pupil learning. From concerns articulated by teachers three instructional needs emerged: (i) to make subject progression, especially in biology, and pupil learning more visible, (ii) to develop mathematics teaching in order to change pupils’ views of the subject, and (iii) to develop teachers’ subject matter knowledge and teaching in an ongoing collaborative process.  The paper argues that in order to stimulate teacher professional development it is important to make teacher concerns and thereby needs explicit. They help teachers to identify and reflect on relations between teacher subject matter knowledge, pedagogical content knowledge and pupil learning.