Aim: The Breast Care Nurse (BCN) supports people with breast cancer, co-ordinating services, and providing information and psychosocial support, yet there is ambiguity surrounding the scope of the role, with implications for both BCNs and service provision. The current studies investigated the scope of practice of BCNs from the perspective of both BCNs and other health professionals. Method: In study 1, semi-structured in-depth interviews were conducted with 11 BCNs and 7 other key health professionals (HPs) involved in the care of those with breast cancer. Participants were questioned about the scope of practice of the BCN role and the challenges facing the role. In Study 2, 27 BCNs and 21 HPs then completed a survey asking about the importance of the different elements of practice identified in Study 1, together with the extent to which each aspect of practice was part of the day to day practice of BCNs. Results and conclusion: Provision of information and support to people with breast cancer and their families were identified as core to the role. BCNs and other health professionals differed in their perceptions of both the length and breadth of practice of the BCN, with implications for workload and burnout in BCNs, as well as multidisciplinary team functioning and patient care. Scope of practice also differed across practice contexts.