Preschools in Sweden are facing increasing requirements for introducing quality systems, and documentation practices are becoming a central part of the preschools' work. This article examines how Swedish principals perceive the assignment of documentation regarding special educational needs (SEN). Drawing on the theoretical work of Schön, this study explores how preschool principals describe the purpose and value of SEN documentation and their own role in its practice. The findings suggest three positions towards SEN documentation, described as: "Resisting," which questions the purpose of the documentation and its target group; "Accepting," where documentation is used as a useful administrative tool and for structuring working practices; and, an "Enthusiastic" position, highlighting the benefits of documentation for individual children, staff members, and the organisation. The findings indicate that principals have a large scope for autonomy to shape and use different types of professional knowledge, which reflects different articulations of the best interests of children.