This study is an investigation into what mentees and mentors perceive they are learning and what factors contribute to this learning within formal mentoring relationships. A qualitative case study approach was taken to review mentors? and mentees? learning at regular intervals throughout a pilot formal mentoring programme within a West Midlands Healthcare Trust. The results are presented within four categories of learning: cognitive skill-based affective-related learning and social networks. They demonstrate the changing scope of learning as process and product and the impact of moderating factors on the mentoring relationships. These findings have practical implications for the development and design of formal mentoring programmes elsewhere.