Mentoring relationships can have both costs and benefits for mentors and their proteges. The present research examined the degree to which mentors' perceived costs and benefits affect the functional and dysfunctional mentoring they provide to their proteges. Additionally, I investigated whether mentor-perceived costs and benefits were associated with the mentors' own goal orientation and the goal orientation of their proteges. Data were collected from 86 proteges and their current supervisory mentors. Consistent with expectations, when mentors reported greater costs of embarrassment associated with their relationship, the proteges reported receiving greater dysfunctional mentoring. Proteges who reported receiving greater functional mentoring tended to have mentors who perceived greater benefits of mentoring them. Both proteges and mentor goal orientations demonstrated significant correlations with mentor-perceived costs and benefits of their relationships. Implications for training and reinforcing functional mentoring will be discussed.