Teacher mentoring programs have increased dramatically since the early 1980s as a vehicle to support and retain novice teachers. However, researchers and facilitators of mentoring programs are recognizing that mentors also derive substantial benefits from the mentoring experience. This digest examines research on how mentoring contributes to the ongoing professional development of experienced teachers. Benefits to mentors include improved professional competency, increased reflective practice, teacher renewal, enhanced self-esteem, improved teacher collaboration, and development of teacher leadership. Working with new teachers can also lead mentors to participate in university research projects or teacher research. The benefits of mentoring programs have important implications for funding decisions made by administrators and staff development personnel. Principals must understand that creating a structure that allows experienced teachers to work with novice teachers will ultimately benefit the students, and the overall organization will be stronger as a result of the increased capacity of teachers serving as mentors. Staff developers should embrace mentoring programs not only as a valuable resource for beginning teachers, but also as a growth-promoting experience for mentors. (Contains 23 references.) (SM)