The purpose of this study was to investigate how the music as a discipline has been given a certain role in the preschool setting both from the curriculum, but also when it comes to how the preschool teachers, with different musical background, reflects upon and practice their knowledge or non-knowledge of popular music in preschool. Through case study with observations and interviews, four themes have been explored from Foucault’s theory of discourse, discipline, knowledge and non-knowledge, 1. The curriculum’s contribution of shaping music as a discipline. 2. The instrumental use of music and it’s unspecific place 3. Music as knowledge and non-knowledge, and 4. Inadequacy and free interpretation of the curriculum. The result of this study showed that the curriculum contributes to make music as a discipline ambiguous through how the music is portrayed in relation to other subjects as mathematics. The pedagogue’s different practices and reflections about the music shows on widely different pictures of what working with music involves and all of this makes the music's status unclear and therefore takes many different shapes and definitions with the work of music where the perception of musical work can change a lot from pre-school to pre-school.