The study reported on in this paper is set in the context of a national programme of professional development for primary teachers in the Republic of Ireland which has been in operation since 1999 and finished in 2008. The paper explores the acquisition and interpretation by teachers of the elements of the reform. The authors consider the extent to which the professional development experiences facilitated change in teachers' knowledge and if the teachers interpreted this in the way expected by policy-makers. The theoretical basis to the study draws on previous research that conceptualises teacher learning/knowledge acquisition and the change process as being dependent on an interwoven mix of factors, including teacher, school and policy-level contexts and characteristics. To a large degree the findings of this study do not deviate wildly from this prior work, which suggests that policy-makers and planners of continuing professional development (CPD) programmes, despite their best intentions, still need to be cognisant of such factors. (Contains 6 tables and 2 notes.)