It is hoped that by recruiting students who are competent in mathematics into primary school teaching, standards will improve. We examined whether there is a correlation between attainment at a state run examination taken by Irish students at school completion (Leaving Certificate (LC)), and competency in primary school mathematics and the possibility of establishing a minimum threshold level of competency from this. We also examined the potential effects on enrolment into initial teacher education (ITE). 124 first year ITE students completed a standardised attainment test typically taken by children in final year of primary school and a questionnaire. Results were compared with their LC mathematics grades. Only moderate correlation was found between the two scores (r=0.54). A proposed revised threshold level would have excluded 40% of competent students. Mathematics grades at school leaving appear to be an unsuitable single measure for establishing a threshold entry requirement for ITE.