This paper reports findings of a one-year collaborative research project examining the role of experienced teachers as mentors to new members of the teaching profession. Mentoring practice was studied in PETE programmes in the Republic of Ireland, Northern Ireland and England and was funded by the Standing Conference on Teacher Education North and South (SCoTENS). Research participants comprised six University tutors (UTs) and ten PE mentor teachers across the three national research sites. A range of data collection methods (synchronous and asynchronous) were employed and data were analysed thematically using a constructivist version of grounded theory (Strauss and Corbin, 1998, p.141, Charmaz, 2000). This paper reports one of the five key findings from this study i.e. ‘Mentors need to be selected on the basis of suitability i.e. disposition and expertise and must be trained to mentor pre-service teachers effectively’. This finding indicated that ‘suitable mentors’ used particular mentor pedagogies and moreover the quality of mentoring was influenced by a continuum of factors. Conclusions point to a possible way forward for the Irish teaching profession i.e. focusing mentor training on the development of effective mentor pedagogies, and to conceptualise mentoring as a profession-building activity for all members of the teaching community.