From 2012 to 2016 all teachers of mathematics, in primary through to upper secondary and adult education, in Sweden are to be given the opportunity of receiving state-coordinated professional development (PD), generally involving around one meeting per week for a year. We examine the ways in which this programme and its content are research-based by analysing the design principles of the PD and its content via a review of the underlying documents. We find that the research base for the design of the PD decisions is formulated only partly explicitly in the documentation, as is the case for the content. Nevertheless, the principles still largely conform to internationally recognised research-based models for PD and teacher change. In the discussion we propose that a relatively open design process, involving many stakeholders with knowledge of both theory and practice rather than an analytical examination of previous research, has contributed to the adoption of this format for the PD programme.