Objective To investigate NHS doctors' perceived benefits of being involved in mentoring schemes and to explore the overlaps and relationships between areas of benefit. Design Extended qualitative analysis of a multi-site interview study following an interpretivist approach. Setting Six NHS mentoring schemes across England. Main outcome measures Perceived benefits. Results While primary analysis resulted in lists of perceived benefits, the extended analysis revealed three overarching areas: professional practice, personal well-being and development. Benefits appear to go beyond a doctor's professional role to cross the personal–professional interface. Problem solving and change management seem to be key processes underpinning the raft of personal and professional benefits reported. A conceptual map was developed to depict these areas and relationships. In addition secondary analysis suggests that in benefitting one area mentoring may lead to consequential benefits in others. Conclusions Prior research into mentoring has mainly taken place in a single health care sector. This multi-site study suggests that the perceived benefits of involvement in mentoring may cross the personal/professional interface and may override organizational differences. Furthermore the map developed highlights the complex relationships which exist between the three areas of professional practice, personal wellbeing and personal and professional development. Given the consistency of findings across several studies it seems probable that organizations would be strengthened by doctors who feel more satisfied and confident in their professional roles as a result of participation in mentoring. Mentoring may have the potential to take us beyond individual limits to greater benefits and the conceptual map may offer a starting point for the development of outcome criteria and evaluation tools for mentoring schemes.