State legislatures and school systems have mandated or recommended mentoring supports for inexperienced teachers. This paper describes a program designed to recruit retired New York City public school teachers to be trained to serve as mentors for newly hired teachers. The study of the training program focused on the interface between the training experiences and the retired teachers' attitudes and behaviors as they became involved in the complexities of mentoring. An essential perspective built into the training design was that retired teachers were viewed as master teachers with valued expertise. Selected retired teachers participated in three separate, intensive, four-day pre-school workshops of 18 hours each. The workshops included large and small group discussions, role playing, demonstrations, and analysis of videotapes. The results of an analysis of the program's effectiveness are presented in three sections: phases of the transition from master teacher to mentor, comparisons of elementary and secondary teachers during the initial training, and comparisons across training sessions. Three tables are included. (JD)