This study is based on the impact of a five-week teaching practicum on the selves of nine cooperating teachers who voluntarily handed over their classrooms to student teachers. Cooperating teachers in Ireland do not have an official role in either mentoring or assessing their student teachers. Because the study focused on aspects of the self that included identity, role, perspectives, relationships and emotions, I used symbolic intercationism as a theoretical framework. I decided that semi-structured interviewing was the most effective method of accessing the selves of the teachers in allowing them to articulate their experience of the practicum. The teachers were interviewed prior to, during and after the practicum. The process of literature review and data analysis was iterative in that each of these two components informed the other. Four main themes emerged: defining the situation, negotiation, perspectives and emotions.A meta-analysis of the data in relation to the theoretical framework revealed how cooperating and student teacher held competing definitions of the same situation and how cooperating teachers used a range of strategies to negotiate the meaning of the practicum. It also showed that the practicum impacted strongly on the self-identities of the teachers. A strong sense of self was evident prior to the practicum. This was followed by a period of mortification arising from an erosion of their self-identities as their role became peripheral in the classroom. In response they had to re-define the situation by assuming other roles, leading to a re-affirmation of self, gaining a better knowledge of their pupils and realising their own competence as teachers. While the focus of this study is at the micro-interactionist level, there are broader implications. Because of the emotional impact of the practicum, there is an urgent need for the teacher education institution to engage with cooperating teachers and to recognise and support them for the emotional journeys that engagement in the teaching practice involves. There are also structural implications insofar as the design and conducting of any mentoring programme should take cognisance of the self of the cooperating teacher
