This study explored the perceptions of mentor teachers about the impact of mentoring on them. The study involved cross-cultural collaborative research between an American and an Israeli teacher education program and a collaboration within each country between the teacher education program and its elementary professional development school (PDS). Mentors received training in cognitive coaching and participated in ongoing dialogue. Data collection in each country involved observations, conversations, and end-of-year questionnaires which investigated the benefits of mentoring for mentors. In each country, reflection sessions with mentors shared data that had been collected from their peers abroad. Results indicated large differences between American and Israeli mentors in their perceptions of what they gained from the mentoring experience. Both groups believed that the mentoring experience influenced their work in the classroom. Mentoring also influenced both groups' professional and private lives beyond the classroom. The dialogue meetings and reflection sessions were the most important components in developing awareness and understanding of mentors' roles in the PDS. Mentoring required a long time to develop, with teachers coming to grips with their new roles after spending time (often years) in the process. All mentors acknowledged the crucial role of training in cognitive coaching for their mentoring activity. (Contains 38 references.) (SM)