This study deals with novice teachers' mentors' conceptions of mentoring prior to their mentoring training. In Israel, all novice teachers have to be supported and assessed by a mentor during their first year of teaching. The aim of this study was to elicit from prospective mentors their own conception of professional mentoring, as a basis for developing mentor training courses. We administered a questionnaire to 170 experienced teachers who had just started taking mentor courses in Israel. The open-ended questions therein included five category components: the mentor's spheres of responsibility; content addressed in mentoring work; qualities required in mentors; professional skills required for mentoring; and indicators of successful mentoring. The findings mapped perceptions of the role of mentors but also revealed missing elements. The concluding discussion of the findings provides insight into the planning of training programs for mentors of novice teachers, thereby optimizing the training process and the professional abilities of their graduates.