Prof Merrilyn Goos presented at the 42nd Mathematics Education Research Group of Australasia (MERGA) Conference at Curtin University, Perth, Australia (30th June – 4th July, 2019). The presentation entitled: Impact of a National Professional Development Program on the Beliefs and Practices of Out-of-Field Teachers of Mathematics, was co-authored by Prof Merrilyn Goos, Dr Máire Ni Ríordáin, Dr Ciara Lane and Dr Fiona Faulkner. It reported on a study evaluating the impact of a national professional learning program for out-of-field secondary mathematics teachers – the Professional Diploma in Mathematics for Teaching (PDMT). An online survey investigated teachers’ beliefs about mathematics, mathematics teaching and mathematics learning, and changes in teaching practices. These teachers reported largely child-centred beliefs and practices consistent with the problem-solving orientation of the new mathematics curriculum, thus providing some evidence of the program’s impact.