Recent thinking about policy on cancer services in the UK has highlighted the importance of recognising the needs of carers, but is unclear about the ways in which this might be done. Our recent study on the psychosocial needs of cancer patients and their main informal carers was unusual in its combined focus on patients and carers experiencing the ‘cancer journey’ together. One of our aims was to contribute to an understanding of what it means to be the main carer of someone with cancer. Using the qualitative data from the 79 carers and patients we interviewed, we ask how carers negotiate their place in the cancer situation, and particularly how do carers identify their role in relation to the patient and the medical setting? We posit carers as taking part in a shifting process of ‘carerhood’ in which competing needs vie for space. Our evidence suggests carers actively negotiate the challenges of their position in dealing with issues of identity, support, and sharing. We suggest that when the carer's involvement in the cancer scenario is recognised and legitimised by others it is easier for them to attend to their own needs alongside those of the patient.