This study examines the mathematical content knowledge (MCK) of pre-service post-primary mathematics teachers (N=85) on commencing their Professional Master of Education (PME) initial teacher education (ITE) programme. Participants’ cognitive and conceptual proficiency with curriculum-aligned mathematical content was evaluated using a validated paper and pencil test, on commencement of their PME studies. Findings indicate that pre-service mathematics teachers exhibit stronger proficiency with Junior-Cycle curriculum-aligned content and weak proficiency with Senior-Cycle concepts, regardless of the curriculum strand. Given the lack of recent research examining MCK relating to pre-service teachers, and the focus of postgraduate ITE programmes on pedagogical aspects of teaching, this research identifies concerns with ITE programmes that may need to be addressed to support pre- service mathematics teachers’ development and induction into the profession. Keywords: mathematical content knowledge; pre-service teachers; consecutive ITE