Mentoring programs can enhance nursing satisfaction, improve retention, ensure optimal patient outcomes, and may have a positive organizational effect in developing leadership skills in nursing. In this study, the effects of a formal mentoring program were explored on a sample of 18 professional nurse leaders (nine mentors and nine proteges) at a university hospital in Turkey. After receiving a formal mentoring training program, mentors and proteges were paired with each other for a 6-month monitoring period. An overall assessment revealed both mentors and proteges perceived benefits from the mentoring program. The formal mentoring program created positive change in leadership behaviors for both mentors and proteges and contributed toward relational job learning for mentors and personal skill development for proteges. Suggestions are provided for the integration of formal mentoring programs into the organizational culture.