This study investigates the relationship of formal mentoring program design elements (i.e., voluntary participation, input to matching, and effectiveness of training) and management support to the benefits and costs perceived by formal mentors. Data were collected from 97 formal mentors from a Midwestern financial institution. Multiple regressions were performed controlling for time as a mentor in the program, hours spent mentoring, and number of proteges. Voluntary mentor participation was positively related to perceiving rewarding experiences and negatively related to being more trouble than it was worth. Input to the matching process was negatively related to nepotism, and perceptions of training effectiveness were positively related to generativity. Finally, perceived management support for the program was positively related to rewarding experience and recognition, and negatively related to generativity and bad reflection. Three supplemental group interviews were conducted to further explore some of the survey findings. Directions for future research and implications for formal workplace mentoring programs as well as mentoring programs in cross-disciplinary contexts are discussed.