Little has been published regarding the development of therapists during their professional lives (Skovholt & Ronnestad, 1992), or about the individual development of marriage and family therapists (Benningfield & Benningfield, 1992; Simon, 1992). This qualitative research study explored the development of marriage and family therapists (MFTsS) using one-on-one in depth interviews that were videotaped. The purpose was to identify important events and themes in the lives of marriage and family therapists and to identify important theoretical components of MFT development. Eight marriage and family therapists who were graduates of an accredited MFT training program and/or clinical members of the American Association of Marriage and Family Therapy were interviewed and videotaped. The Videotapes were reviewed and analyzed by the author, using the grounded theory research approach of Strauss and Corbin (1999) as a guide. The author compared reported events and themes to basic developmental concepts outlined by Lerner (1986). The main developmental theme was the integration of the personal and professional selves (labeled synthesis) of the participants. The most important ingredients in the participants’ development seemed to be developmental motivation, resiliency, balance and balancing strategies, and awareness. Continued development was closely associated with continued synthesis, careful monitoring of boundaries, and creative use of developmental motivation. It was the interaction between events, awareness, developmental motivation, and resiliency which produced growth. Information gained from this study may be useful in understanding the self of the therapist within training and supervision, and it may serve as a map of the possible transitions facing a therapist along the journey of development. With this study the author hopes to stimulate interest in additional research on marriage and family therapist development. / Ph. D.