This study investigated how six mentor teachers understood and negotiated their roles as mentors in an elementary professional development school (PDS). Data were collected over 18 months from mentor and intern journals, field notes, interviews, e-mails, meeting minutes, and transcripts from PDS meetings. Each teacher participated in interviews regarding their motivation and teacher education experiences, experiences as mentors within the PDS, and thoughts associated with problems and possibilities of the PDS. Results are discussed according to three PDS phases. In the first phase, teachers were not committed to the renewal piece of the vision and were not always comfortable using their voices, though they often silenced their colleagues to protect their established ways of doing business. In the second phase, teachers' work changed in meaningful ways as they incorporated interns into the classroom. Teachers grew professionally as they dialogued with interns. The mentor role broadened to include beginning teacher educators. In the third phase, mentors engaged in some form of inquiry, seeking to understand what inquiry was and how it was part of their work. They used observation as a tool for understanding inquiry and began to recognize inquiry as a professional development tool for interns. (Contains 26 references.) (SM)