In what way might writing of different kinds contribute to the development of a professional identity? By analytically distinguishing three discourses of communication, everyday, professional and academic, applied to three preschool student teachers’ conceptions of writing during their education and in their initial phase at work as preschool teachers, we attempt to understand the role of writing in their development of professional identities. What we have found is that the professional discourse which all three have achieved is something each of them creates and develops in very different forms. Their independent final projects show that all three have a mastery of academic discourse, but only in exceptional cases do they make use of that discourse in contexts other than this specific piece of work and to some extent earlier papers written as part of their teacher education. However, judging from our interviews and their responses to our questions, it seems as if they have acquired modes of expression quite close to an academic discourse, but have primarily developed and use different variants of a professional discourse. This professional discourse also seems to be an important element in their development of a professional identity.